One reason could be a divergence from the original friendship dynamic in the books. In the canon, Harry and Ron are good friends, and fanfiction that shows Harry hating Ron might go against what many fans consider the essence of their relationship.
Some writers might create such fanfiction for the shock value. They want to break the established strong friendship in the original series to get readers' attention.
Maybe some people just want to explore a different and darker side of their relationship. In fanfiction, creators often take liberties to show complex emotions that might not be as obvious in the original books. Harry hating Ron could be a way to create drama and new storylines.
One possible theme could be betrayal. If Harry hates Ron, there might be a backstory of Ron doing something that made Harry feel deeply betrayed. Another theme could be jealousy. Maybe Ron has something that Harry desires, which leads to this hatred.
Yes, there might be some out there. Fanfiction is a vast and diverse world where writers explore all kinds of alternative scenarios. However, this goes against the core friendship in the original series. It's like a dark, twisted take on the relationship between Harry and Ron.
It also shows the freedom and diversity in fanfiction. While it might not be in line with the original spirit, it allows for different creative ideas to be explored. However, it can cause some division within the fan community between those who support this new take and those who firmly oppose any deviation from the original relationships.
Maybe in the fanfic, there could be a misunderstanding between them. For example, Ron might have accidentally broken Harry's trust in some way, like revealing a secret of Harry's that he wasn't supposed to.
It could also influence other fan works. If this type of fanfiction becomes popular, it might inspire more works that explore negative relationships between the main characters. This could change the overall tone of the fan community's creations, moving away from the positive and friendly relationships that are often emphasized in the original books.
To explore different character arcs. Maybe they think that if Harry hated Ron, it would force both characters to grow in different ways. It could be a way of looking at how their personalities would develop without their friendship. Also, it could be a way to introduce new plotlines and conflicts in the Harry Potter universe.
It can divide the fandom. Some fans who love the Hermione - Ron relationship in the original series might be put off by such fanfiction. They might feel that it goes against the spirit of the story they love.