Another reason could be that the Rookie Nine have different goals or values that conflict with Naruto's. For instance, if they are more focused on self - interest rather than the greater good that Naruto is always striving for. This divergence in values might lead to Naruto's dislike and eventually hatred for them. And also, personal conflicts within the group that Naruto gets caught in the middle of could be a factor.
Perhaps in the fanfic, there is some sort of power struggle within the group. The Rookie Nine might be trying to undermine Naruto's position or influence. This could make Naruto feel threatened and result in him hating them. Additionally, if there are new members added to the Rookie Nine in the fanfic and they change the dynamics in a negative way for Naruto, it could also contribute to his hatred.
It could be that in the fanfic's storyline, the Rookie Nine have made some choices that go against Naruto's ideals. For example, if they side with a character or a group that Naruto sees as wrong. This could lead to his hatred. Also, perhaps there has been some miscommunication among them, and Naruto takes it the wrong way, which gradually builds up his negative feelings towards them.
Perhaps he thinks fanfic undermines the integrity of the original Naruto story. The official story has a certain narrative and character development, and fanfic can deviate from that significantly. When it comes to his connection with Naruto, any deviation in fanfic might be seen as a negative. For example, if a fanfic changes the way he mentors Naruto, it could be something he wouldn't like.
The power scaling might be another issue. Naruto has a very detailed and complex power system that is based on chakra, jutsu, and ninja ranks. Fairy Tail has its own magic - based power system. In fanfics, getting these power systems to mesh well can be difficult, and Naruto might 'hate' being part of a poorly - balanced power - system fanfic.
One reason could be that some fans are very purist about the original Naruto story. They might feel that fanfiction often distorts the characters or the plot in ways that go against the essence of what Naruto is all about. For example, changing a character's personality completely to fit a romantic or dark and edgy narrative that doesn't align with the source material.
The different power scales. Naruto has his own progression of power through training and ninja ranks. Superman's power is on a completely different level like being able to move planets. In fanfiction, it might be hard to balance their powers in a way that makes sense to Naruto fans, so Naruto might seem to 'hate' it.
Perhaps in fanfiction, Boruto is associated with a group or ideology that Naruto opposes. This could cause Naruto to view Boruto unfavorably. Also, if there are false rumors or misinformation spread in the fanfiction world about Boruto, Naruto might believe them and start to hate Boruto until the truth is revealed. And sometimes, it's just a way for the writer to make an interesting and unexpected plot twist.
One reason could be that the fanfic distorts the characters he knows well from Gryffindor. For instance, if it changes the personalities of his friends in Gryffindor in a way that doesn't seem right to him.
Maybe the fanfic often misrepresents the nature or relationship of Bellatrix and Rodolphus. For example, if in the original they are portrayed as very dark and loyal to a certain cause, but fanfic makes them out to be something else entirely, like soft or good - hearted, it could lead to dislike. Also, some people who are die - hard fans of the official story just don't like the idea of others taking creative liberties with their beloved characters.
Maybe in this fanfic, the author wants to create a unique and dark plot. Kushina might be made to hate Naruto due to some kind of misunderstanding. For example, she could be misled to believe that Naruto has some connection to a great evil that she is against.
A possible reason could be jealousy. If Naruto had a sibling who was always favored by their parents, he might grow to hate his family. He would feel like he was always in the shadow of his sibling and that his family didn't care about him as much.