It could be due to a sense of abandonment. Fanfic writers might explore the idea that Harry, growing up without his parents, feels resentful. He may see other kids with their families and, in his confusion and pain, start to hate his parents for leaving him alone in the world, even though it was not their choice.
Another reason could be creative reinterpretation. The fanfic might be set in an alternate universe where Harry's parents made choices that conflicted with Harry's values. For instance, if they were involved in some dark magic experiments in this fictional version, Harry could hate them for going against what he believes is right.
In some fanfictions, Danny Phantom may hate his parents because they are constantly trying to hunt him down. His parents are ghost hunters and they don't know that Danny is actually half - ghost. So their actions of trying to capture and study ghosts put Danny in a dangerous and uncomfortable position, which could lead to feelings of hatred.
One possible reason could be that in the fanfic, the author might twist the story to make it seem like his parents' actions had unforeseen consequences that affected Harry negatively. For example, their fight against Voldemort led to Harry being an orphan and having to bear a great burden from a young age.
Perhaps Harry has his own vision of Gryffindor and the fanfics he's seen don't align with it. He might have a deep - seated understanding of what Gryffindor means to him, like courage, loyalty, and friendship in a very personal way. The fanfics, on the other hand, might focus on more superficial or inappropriate aspects of Gryffindor for his taste, such as focusing too much on power plays or false bravado rather than the true essence of what makes Gryffindor great.
In some fanfics, Harry might hate Dumbledore because he feels Dumbledore has been using him all along as a tool to defeat Voldemort. Dumbledore has been making decisions for Harry without fully considering Harry's feelings and desires. For example, he didn't tell Harry about the prophecy until it was almost too late, and Harry might see this as a form of manipulation.
It could be that in the fanfic's plot, McGonagall has some past connection to Harry's enemies. So, her hatred towards Harry is a result of her loyalty to those she has a history with. This would create a lot of drama and conflict within the fanfic's story.
Well, it could be that he has seen some really bad magic fanfic. Some fanfic might be full of inaccuracies about magic, and as someone who has a deep connection to magic, it annoys him. For example, if a fanfic misrepresents a spell or a magical creature that he is familiar with, it would make him dislike it.
In some fanfiction, Harry might hate his brother due to jealousy. Maybe the brother gets more attention from their parents or is more successful in certain areas, like magic if it's in a Harry Potter - inspired fanfic. This can create a rift between them.
In the fanfic, it could be that there are some misunderstandings within the team. Naruto might think his team doesn't support his dreams or goals. His teammates could be too self - centered in the story, always putting their own interests first and ignoring Naruto's needs. This would lead to Naruto developing negative feelings towards them.
In some fanfics, Naruto might be depicted as hating his friends due to a misunderstanding. For example, if a false rumor spreads about his friends betraying him, he could start to harbor negative feelings. Another reason could be a dark magic or curse that alters his perception of his friends, making him think they are not who they seem.
Maybe he hates it because it often distorts the real story or characters he knows. Fanfics can take the story in wild directions that don't align with his own experiences.