Another reason could be that she values the authenticity of the original Naruto narrative. Fanfictions are often the product of fans' wild imaginations and might not align with the official story. She might be a purist when it comes to the Naruto story she is a part of, and thus hates fanfiction that strays too far from the original.
Maybe in the fanfic, Itachi has done something that goes against Sakura's beliefs or values. For example, he might have made a decision that put her friends in danger.
Well, in fanfic, the writer can take creative liberties. It could be that Naruto has grown and evolved in a different way than in the original story. He might have seen Sakura's flaws more clearly over time. For example, her obsession with Sasuke could be seen as a negative trait that affects the team dynamic. And as Naruto values the team highly, this could cause him to develop a dislike and eventually hate for Sakura.
It could be that in the fanfiction, Naruto's character is developed in a way that Sakura, within the sasunaru concept, doesn't approve. For instance, if the fanfiction makes Naruto too weak or too different from his original self. Also, if the fanfiction focuses too much on certain relationships that she doesn't like, she would hate it.
Maybe you haven't found the right type of literature yet. There are so many different genres out there, like science fiction, mystery, or even graphic novels. Try exploring different styles and you might change your mind.
Look for books that are related to your hobbies or interests. For example, if you like sports, there are many sports - themed novels. This might make reading more enjoyable for you.
Sinfest is not a hate comic. It may have themes or depictions that some find challenging, but it doesn't have the intention of promoting hate. The interpretation of what constitutes a hate comic can vary greatly among individuals.
Maybe humans have been over - capturing Pokémon without considering their well - being. In the fanfic, this could lead to Pokémon feeling like they are just objects to be collected. So they start to hate humans.
Madara Uchiha is another character who could be central in such a fanfiction. He had his own reasons for hating the world and seeking power. The 'power of hate' in a fanfiction could be used to delve deeper into his motives and actions, perhaps showing how his hate not only influenced his own life but also had far - reaching consequences for the entire Naruto universe.
Perhaps the development of the characters felt forced or the overall storyline was too predictable. Maybe there was a lack of depth or complexity that you look for in a manhwa.