One possible reason could be that his family in the fanfiction might be cruel or neglectful towards him. Maybe they constantly put him down or don't support his dreams and ambitions, which would lead to his hatred.
One possible reason could be the way the Dursleys treated him. They were cruel, made him live in a cupboard, and constantly belittled him. This kind of mistreatment over the years could easily lead to hatred. Another aspect could be the lack of connection to his wizarding family that he was not aware of for a long time. He might feel angry at his parents for leaving him in such a situation without any real protection from the Dursleys.
The plot might start with Harry gradually realizing his family's true nature and starting to distance himself from them. As he pulls away, there could be a lot of conflict and drama within the family.
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 completely flips the usual narrative. In the original story, Harry has a sense of longing for his family, especially his parents. But in this fanfiction, the hatred changes the emotional core. It makes Harry a more complex and perhaps darker character. The relationships that were once sources of strength, like his connection to his parents through their sacrifices, now become sources of bitterness.
One good fem Harry hates her family fanfiction is 'The Unwanted Daughter'. In it, Harry as a female character endures a lot of mistreatment from her family. It shows her struggle to break free from their negative influence and find her own path. The author does a great job of portraying her emotions.
One way could be through Naruto feeling neglected by his family. Maybe in this fanfiction, his parents were alive but were always too busy with village affairs, leaving Naruto feeling alone and unloved. This could lead to his hatred as he grows up seeing other families being more present for their kids.
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 common theme is isolation. Since fem Harry hates her family, she often feels alone. Another theme is self - discovery. As she breaks away from her family, she has to figure out who she really is. For example, in many stories, she discovers new magical abilities or aspects of her personality.
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.