One possible reason could be a misunderstanding. Perhaps Naruto misinterprets some of his family's actions or words. Maybe he thinks his family didn't care about him as much as he thought they should. In fanfiction, authors often play with the idea of miscommunication and how it can lead to strong negative emotions like hatred. Also, if there are other characters in the fanfiction who influence Naruto's view of his family, say by spreading false rumors or manipulating him, that could contribute to his hatred.
It can be quite divisive. Some fans might be extremely offended as Naruto is a beloved character known for his positive traits. This type of fanfiction goes against the established character arc and values. It could make some fans angry that someone would distort Naruto's character in such a way.
The plot might start with Naruto gradually realizing certain things about his family that make him feel angry or betrayed. For example, he could find out about a hidden deal his family made that he doesn't agree with.
One possible reason could be that he discovers some long - hidden family secrets that make him feel betrayed. For example, if he finds out that his family was involved in something unethical in the past. Another reason might be that he feels constantly overshadowed by his family's legacy and can't form his own identity within the family, so he decides to leave to find himself.
Well, it completely flips the original Naruto story on its head. In the original, family was something Naruto always longed for, so having him hate his family in the fanfiction is a huge departure. It makes the story much darker.
Well, it's possible that there is a 'Naruto is homicidal hates his family' fanfiction. If so, the plot could be set in a world where Naruto discovers some sort of dark secret about his family that he misinterprets. For example, he might find out that his father sealed a powerful and dangerous entity within him, and instead of understanding the sacrifice his father made, he sees it as an act of aggression. As a result, he starts to hate his family and becomes homicidal. But again, this is a very different Naruto from the one we love in the original work.
One way to justify it could be through a series of betrayals. Maybe Naruto discovers that Konoha has been using him all along, and his family has some dark secrets that make him feel betrayed. For example, if he finds out that his father was involved in some unethical experiments that led to the suffering of many villagers, that could turn him against both Konoha and his family.
A potential plot twist could be that Naruto's hatred is actually a cover - up for his love. He might be pretending to hate Konoha and his family to protect them from a greater threat. Maybe there's an enemy who would target them if Naruto showed any affection, so he creates this false front of hatred.
It shows his growth from being someone who initially had some family - related issues. By hating his family and leaving, he starts to become more independent. He has to face the world on his own terms, which forces him to develop new skills and a stronger sense of self.