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.
In the fanfiction, it could be that Naruto experiences a major event that makes him lose faith in his family. For instance, if his family fails to protect someone he cares about deeply. This could cause him to resent them. Also, he may have met new people outside the family who show him a different way of life that he desires more, so he hates his current family situation and leaves.
It could also be due to differences in values. If Dark Naruto had different beliefs about power, friendship, or loyalty compared to his family, and they constantly clashed over these, it might lead to his hatred. For instance, if his family adhered strictly to Konoha's traditional values but he saw them as restrictive.
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.
Maybe Naruto has some sort of disagreement or falling - out with his family. This could lead him to seek a new start in Kiri. For example, if there are differences in values or expectations within his family that he can't reconcile with, he might choose to leave.
Another reason might be related to family politics. In some complex family structures in the Naruto universe, there could be different factions. Naruto might be on the wrong side of the power struggle within the family. His views or actions could be seen as a threat to the traditional power structure of the family, so they hate him.
One possible reason could be jealousy. Maybe Naruto has some special abilities or a prophecy surrounding him that makes his family members, who might be less favored, jealous. For example, if there's a prophecy that Naruto will be the most powerful ninja in the village, his siblings or parents might envy that future for him and start to hate him out of their own insecurities.
In some fanfics, Naruto might leave his family because of a dangerous threat approaching them. He could believe that by leaving, he would draw the danger away and keep his family safe.
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.
It could also be due to some external influence. Perhaps an enemy manipulated Naruto's mind in the fanfiction, making him see his family in a negative light. This enemy might have used some form of mind - control or false memories to turn Naruto against his family.
One possible reason could be feeling neglected. Maybe his family was always preoccupied with other matters, like protecting the village, and didn't give him enough attention. So he grew to resent them.
One possible reason could be jealousy. Maybe his brother has some special abilities or gets more attention that Naruto feels he should have. For example, if his brother is really good at a certain jutsu and is always praised for it while Naruto struggles, that could lead to resentment.