It could be that Peter has his own ideas about Steve, and the fanfiction doesn't align with his views. For example, if the fanfiction gives Steve a personality trait that Peter doesn't think suits him, like making him overly aggressive when Peter sees Steve as more of a calm leader, he won't like it.
Maybe Peter doesn't like the way Steve is portrayed in fanfiction. Some fanfictions might deviate too much from the original character, and Peter prefers the official version of Steve.
Peter might not be a fan of the genre of fanfiction in general. He could prefer original works and find fanfiction, especially about Steve, to be unoriginal or too derivative. Also, it could be that he has had some bad experiences reading poorly - written Steve fanfiction in the past that has put him off completely.
Maybe Peter Parker has his own distinct view of Steve. He might feel that fanfiction often distorts Steve's real character or the relationships in the original story, so he doesn't like it.
Perhaps Steve in the fanfiction was involved in a cover - up of some sort that affected Peter. Say, Steve knew about a threat coming towards Peter but didn't tell him in time because he thought Peter couldn't handle it. When Peter found out, he felt betrayed and thus couldn't forgive Steve. Also, if Steve accidentally caused harm to one of Peter's friends or allies while on a mission, that could be a major factor in Peter's unforgiveness.
It might start with a small incident where Steve dismisses Peter's ideas or concerns. This initial rift then grows as more events unfold. For example, Steve might take credit for something Peter did, which makes Peter angry and less likely to forgive.
Well, in some fanfictions, the author might want to create an alternate scenario where Harry has different relationship dynamics. Maybe they want to explore other pairings for Harry and so they write him as not liking Ginny to deviate from the original storyline.
It could be that she simply wants to keep her real relationship with Edward private. Fanfictions might make her feel like her relationship is being overly exposed or misrepresented. For example, some fanfictions might add in elements that she finds uncomfortable or not true to their actual connection.
Maybe in those fanfictions, the author portrays McGonagall in a way that Harry doesn't like. For example, the character might be out of character and act too harshly or differently from how he expects her to be in the original story.
Maybe Harry thinks fanfiction often distorts the real relationship between him and Ron. He values their genuine friendship and doesn't like the fictional and sometimes over - the - top interpretations in fanfiction.
Maybe Adam just doesn't like the way Mal is portrayed in fanfiction. Some people have very specific ideas about characters and if the fanfiction doesn't align with his view of Mal, he won't like it.
It could be that Harry has a very specific and personal view of Mcgonagall. The fanfictions often add a lot of fictional elements that deviate from his own perception of her. For example, they might make her act out of character in terms of her strictness or fairness, which he doesn't like.