By “legitimate,” I mean that initially there were deities and the ancient path (which is none other than the path of martial arts). Then these deities created human beings as puppets, as resources to nourish their golden bodies through incense offerings. Then, human beings rebelled against the deities and created their own cultivation path, namely Qi cultivation. Qi cultivation allows one to transcend the limitations of the human being, but those who can achieve perfection, a state of absence of errors, are not Qi cultivators but the deities.

Qi Jingchun was pursuing the unity of the three religions as the 14th realm of Dao integration, but he decided to sacrifice himself for the people of Lizhu Grotto-Heaven. Qi Jingchun initially wanted to save as many people as possible and then leave that place, because, as stated three times in the first season (Qi Jingchun tells him twice, and the MC is reminded of this a third time when he goes to Mr. Qi’s academy for help), “a gentleman doesn’t sacrifice himself to save others.” However, Chen Ping’an ultimately didn’t listen to him, and Qi Jingchun, pushed by Chen Ping’an (which is why Chen Ping’an feels guilty when he find out the truth, despite Qi Jingchun’s telling him “even a good man can be deceived by his principles”), chose to make the decision to die for the sake of those people. However, although Qi Jingchun ultimately chose Li Baoping as his sole direct disciple and Chen Ping’an as his younger brother, (from what I understand) Qi Jingchun decided to leave Chen Ping’an the task of demonstrating the unity of the three religions. (The fact that Qi Jingchun orchestrated a conflict regarding the three religions in Chen Ping’an is mentioned during a conversation between the MC and Cui Dongshan. I don’t remember the exact chapter, I think it was about four/five chapters before he goes the second time to find Ning Yao at the Great Wall of the Qi Sword.)
[spoiler title=””] During the second story arc in Old Dragon City, Chen Ping’an states, “My descendants will eventually have to learn to fend for themselves.” “You can’t go against facts and principles just because you feel offended.” In S2 EP7, Chen Ping’an states that he wants to learn as many principles as possible because that way he’ll feel comfortable with his conscience when he has to reason with others, and that by doing so, he’ll be extremely quick and decisive when he has to strike. This all makes a lot of sense, but it’s extremely inappropriate for “the inexperienced 14-year-old Chen Ping’an” to say it, and the Sage of Literature tries to make him understand this during his conversation with the protagonist. This is because fighting is the last thing a person who insists on speaking out of reason wants to do, and the protagonist will understand this; he’ll realize that he’s achieved the opposite effect; the more principles he learns, the more he’ll hesitate to strike.
When Zou Zi says that Chen Ping’an lets go when he rightes grudges but doesn’t let go when he lets Gu Can go, he’s referring to what happens at Shujian Lake but more specifically to the conversation between Chen Ping’an and Master Houlong (his friend Zhang Shanfeng’s master). In that conversation (I really urge you to reread it because I think it’s one of the most important moments of growth of the MC), Chen Ping’an admits his selfishness, admits that as a child he initially helped people because doing so served as a talisman that safeguarded his precarious situation, only later did it become a habit (that’s why in the first season, during their fight, Ma Kuxuan tells him that they were the same, good at pretending), admits that Gu Can should have died and therefore admits why he failed to pass the so-called test of the heart that Cui Chan orchestrated for him. Gu Can had to die for everything he did, that’s an undeniable truth. Chen Ping’an, however, did not kill him and tried his best to find principles that would justify him to not kill his friend, to try to “remedy” the situation by trying to change the petty habits of that place, recovering the souls of the dead by helping them fulfill their last wishes and bringing them back into the cycle of reincarnation—in short, trying to escape from that undeniable truth. However, the more he “runs away,” the more guilty he feels, precisely because the MC is truly a good person. When Chen Ping’an returns home, Cui Cheng tells him, “Whether it’s difficult or not, how you view Gu Can is what matters. I’m questioning your conscience! Does reason really distinguish between close and distant relatives? If you don’t kill Gu Can today, what will you do, Chen Ping’an, if Pei Qian, Zhu Lian, Zheng Dafeng, Li Baoping, and Li Huai of the Academy, or even if I, Cui Cheng, were to commit violence and evil in the future?” And then he tells him, “You’re like a small child carrying a large basket; you won’t amount to anything.” This is precisely where he hits the nail on the head: learning a principle and putting it into practice means that if the situation gets complicated, you’re likely to choose to abandon that principle. But learning a principle and integrating it into your lifestyle means truly assimilating it, and it’s difficult to abandon it (during the Shujian Lake story arc, Old Yang talks about this very thing with Zheng Dafeng). Up until that point, Chen Ping’an had limited himself to “collecting” other people’s principles without ever fully understanding them and truly integrating them into his own lifestyle. In fact, he doesn’t understand that many of the choices he’s made are made according to his heart and have nothing to do with the principles he professes. Even though they may sometimes coincide, they don’t determine his actions.
What Zou Zi fears is precisely this “selfishness” related to Chen Ping’an’s good nature, related to this incessant search for a clear and peaceful conscience by Chen Ping’an, related to the fact that Chen Ping’an obtained that sword but, above all, related to the fact that the MC was decreed by Old Yang as the “winner” of the birth porcelain game (because it’s not simply a way to attract opportunities). [/spoiler]

I don’t understand what you mean when you say “everybody else wants a piece of Ping’an as well?”

The people who spit on Ning Yao’s parents’ swords, rather than hate them, I’d simply call them stupid. I don’t know how far you’ve read the novel, but when the protagonist returns to the Great Wall of Qi Sword for the second time, you’ll be able to understand the atmosphere and the way of life of that place. Yes, I’m talking about the fact that there’s a hole in the walls.

Okay so it was an unjust decision that lead to the path of martial arts being blocked and somebody messed with the position of stars to throw of the divination but there are so many people that keep going to spit on the replicas of Ning Yao’s parents’ swords. And is the giant gap in wall the proof you are talking about?

And also the martial arts being in the state that it is reminds me of body refining in the demon hunter with SHA QI and that technically its not a dead end and actually legitamate, its just that the human body by itself is strong enough to handle the poisonous effects of SHA QI with out some form of modification, whether be starry sky stone or becoming a saint

OH THAT’S WHY, HE’S SO weary of him, he’s worried about what would happen if the world was to return all of the kindness he has shown them, but at that moment he would no longer be that endlessly kind person and He would also be the in the category of qi refiners blessed by the ones above to have highest destructive power of all cultivators, so it was just a test but by going through the test and getting the result he did, Chen Ping An BECAME the kind of person Zou Zi would worry about. NOW I GET IT, I would not have been able to figure that out myself. And the path of martial arts having been “TURNED INTO” a dead end but actually being legit, I am aware, I’ve reached the chapters where Chen Ping An is back at the sword wall so a few things you mentioned I have gotten but Qi Jingchun starting [spoiler title=””] the conflict between the three religions [/spoiler] in Chen Ping An that is not clear at the point I am. But what is the difference between Chen Ping An letting himself go for his own grudges but not letting himself go for Gu Can in Zou Zi’s eyes? Is Zou Zi’s worry the reason why everybody else wants piece of Ping An as well?

Regarding Zou Zi, [spoiler title=””] He is a cultivator from the 14th realm, specializing in the Yin-Yang theory of the five elements (metal, wood, fire, water, and earth). In that scene, he isn’t deliberately targeting Chen Ping’an or making his life difficult; he was simply “testing the waters” by trying to understand the MC’s temperament, waiting to see what choice he would make and the outcome before drawing his conclusions. If Chen Ping’an had taken that tanghulu, as we see his life would have taken a completely different path; he would most likely have become lazy and not developed his perseverance as seen in the [S2 EP25 min11:30]. Zou Zi will continue to keep an eye on the protagonist because what he fears is precisely Chen Ping’an’s temperament, that is, the temperament of someone willing to meddle in the most insignificant matters of the world, and to do so with competence, a pedantic and stubborn person who wouldn’t back down even when faced with a wall and who wouldn’t regret a decision once made. As a child, Chen Ping’an still found joy in hardship, staggering and walking with his burden, smiling and looking to the future with optimism. Zou Zi is pessimistic and believes that if someone like Chen Ping’an should reach the 15th realm as a Sword cultivator, the world might face the worst possible outcome. He thinks the world cannot bear it and that Chen Ping’an will ultimately make a serious mistake. Zou Zi has already understood that Chen Ping’an intends to treat the world with kindness, but he is afraid that all the kindness Chen Ping’an has given to the world, heaven and earth will one day return it (karma) and at that moment, what kind of person might Chen Ping’an be? No one knows: ordinary humans have their own worries and temperaments, cultivators have their own Dao heart, martial artists have their own Dao heart, and Sword cultivators too. The deeper one delves into cultivation, the more one tends to distance oneself from one’s own humanity and mortal concerns. Chen Ping’an prioritizes the cultivation of his mind above all else, even before the cultivation of his body. He reads the literary books of all three religions (not just Confucianism) and various schools of thought, and seeks to embrace the principles he deems correct and consistent. However, there’s a big difference between understanding a principle and then putting it into practice, and understanding a principle and making it your own. When Chen Ping’an will understand this difference, he’ll also understand that introspection, self-discipline, and prudence in solitude aren’t just ways to cultivate the mind, but also to set limits oneself. “Repay kindness with kindness and injustice with justice.” Injustice often breeds resentment. The MC’s childhood was anything but happy. He already harbors enough resentment in his heart. He’s suffered many wrongs and is patiently waiting for the right moment to act [S2 EP15 min11:30]. The question is precisely what would happen if he truly let himself go? Everyone is wary of this, Zou Zi and even various exponents of the three religions and schools of thought. The cultivators with the highest killing power are precisely the sword cultivators and Chen Ping’an at only 14 years old, without significant experience and culture, with a difficult past, has obtained the recognition of the “Sword Holder” (the fairy sister) and also obtained the most powerful sword. As Zou Zi will say towards the last chapters of the novel, Chen Ping’an lets himself go when he settles grudges but he doesn’t let himself go when he lets Gu Can go (Shujian Lake events). Zou Zi is already taking measures in this regard in order to counter Chen Ping’an in the future (I’m referring to the effeminate boy she will most likely meet in the third season), but Qi Jingchun and subsequently Cui Chan (Shujian Lake events) has also already taken measures to protect their junior brother in this regard, Mr. Qi has intentionally orchestrated a conflict between the three religions within MC (This is Qi Jingchun’s real trump card that Cui Chan and Lu Chen talk about in this episode). 
–Chen Ping’an’s mentality at the moment is more Buddhist than Confucian or Taoist, and this can also be seen from the very few principles he expounds throughout this second season: [S2 EP3 min12:26] “seek nothing outside yourself”, of the four phrases found on the Crab Archway in his hometown [S1 EP24 min5:35], this is the only phrase that Chen Ping’an feels is his own and is able to put into practice, and it is also the phrase he says to the white python, which he then kills, wasting one of the three sword Qi when he could have avoided it by asking A Liang for help. This is because Chen Ping’an has always been reluctant to ask for help for himself and never does so if he can manage on his own. Furthermore, this phrase is similar to the principle that Chen Ping’an currently knows and holds dear, taught to him by Old Yao (the master in charge of the porcelain kiln where Chen Ping’an worked as a child), which is “if it’s yours, hold on to it firmly; if it isn’t, don’t dwell on it.” [S2 EP14 min25] and [S2 EP20 min23:35] This phrase harks back to Buddhism, which advises that to find peace, one should release one’s mental grip on things one cannot control or that do not truly belong to one (don’t dwell on it), while fully appreciating the present moment (hold on to it firmly). In fact, Chen Ping’an is stingy with the wealth he possesses, but lacks the greed typical of cultivators when they look for opportunities. Indeed, he will lose many of them, but he will never be discouraged by that. All this is due to this Master Yao, whose true identity is that of the Medicine Buddha.
-However, Chen Ping’an also possesses that “tranquility” [Jing (精), S1 EP24 min4:38] typical of Taoism, sincerity and uprightness that focuses on examining one’s own conscience. You entrust him with a task, however difficult it may be, even if you know he ultimately won’t succeed, no matter how hard he tries, you are still absolutely certain that, if he accepts, he will complete it. Even if he can’t do it with all his strength, he is willing to grit his teeth and give it his all. This is one of the main reasons why Qi Jingchun chose him. 
-However, a Confucian teacher, the Sage of Literature, was chosen for Chen Ping’an, and although he has refused for the moment, Chen Ping’an feels that his teachings are the best and feels deeply connected to the theory of sequential order developed by Master Wensheng. Furthermore, Chen Ping’an has excellent literary talent, good potential to become a scholar, and He has an attitude inclined towards Confucianism. [/spoiler]

Regarding the “extra stuff” I mentioned, I was making a general point about the fact that if we absolutely must stick strictly to the events of the novel, then it should be said that the authors have made much more significant changes than just bringing forward the meeting between Li Baozhen and Chen Ping’an (because I really don’t think it changes much for the plot, that’s my opinion).
Regarding the first part of the comment, I understand that you haven’t read the entire novel and rightly so, you didn’t understand some things.
The reason Cui Cheng gave up on reaching the Eleventh Martial Arts Realm is mainly related to what Cui Chan says to Cui Dongshan towards the end of episode 27. However, here in the novel it is only said that “some people behind the scenes would have created problems” but it is not clear what and who it refers to at least until 800 chapters or more because all this is linked to what happened 10,000 years before the events of the story, to the time that old Yang talks about to Chen Ping’an [S2 Ep24 min 17:30], to the reason why the sword cultivators are mainly found near the great wall of the sword Qi and the demons on the other side, and in particular to that imposing figure seen in ep 27 who is the ancestor of the military strategists Jiang She (who is mentioned by Lu Chen during the fight). In short, it’s not so much about protecting the protagonist but about a much bigger picture, about the unjust decisions, that were made for good, following the events that happened 10,000 years ago, decisions that made “It seems, we are all disappointed with this world” [a phrase Qi Jingchun says in the first season], and the mystery and truth that lie behind the martial arts path that many characters snub but which in reality is the legitimate one, not Qi cultivation.
Regarding the events of the movie, Ning Yao’s parents weren’t the only ones to lose, and people don’t harbor “hate” towards them also because there are two truths behind these 6 defeats: the first is the fact that, as Wei Bo tells it, they relied on divination to deduce the order of the demons’ deployment, and divination uses the position of the stars as a reference but what would happen if someone deliberately moved them? The second is the fact that if the demons had actually taken these 13 battles into consideration then they would have won and the proof is found in the walls in the very first minutes of the first episode of the first season however (if I remember correctly) I think the novel says that this is due to the fact that the “main antagonist” didn’t want the demons to win at that moment.

It’s true that by anticipating the meeting between Li Baozhen and Chen Ping’an things change, but they are not very relevant also because that talisman he takes from Li Baozhen (by the way, Chen Ping’an takes it in this ep) does not have a “very great utility” because he uses it mainly in a specific narrative arc (Shujian Lake) but as Cui Cheng will tell him, if “that cultivator” from the 11th realm (Liu Laocheng) had really wanted him dead, all those external objects would not have changed anything at all. 
As for (Liu Qingshan) “the guy” who is supposed to be with Li Baozhen and the bodyguard in the carriage, in the novel Chen Ping’an meets him anyway before running into Li Baozhen (I’m referring to when “this guy” deliberately sends the carriage off the road to avoid running over Pei Quan) and Chen Ping’an will have the chance to come back and talk to Li Baoping and his family about this only after all these events, so in fact nothing changes practically (they simply deleted the fight between the bodyguard and Zhu Lian). It is true that when he meets Li Baozhen Chen Ping’an shows overwhelming strength but Li Baozhen makes Li Baozhen feel pathetic but he is an ordinary mortal and so it really doesn’t change anything.