It's possible that he associates heroine novels with a certain type of femininity that he doesn't identify with. He may feel that these novels are only for a particular audience, and as someone who doesn't fit into that audience, he hates them. Also, if he has a preference for male - centric stories or stories that are more gender - neutral, heroine novels would be far from his taste.
He might be a person who is more interested in complex plots and deep character development. Heroine novels, in his opinion, might be too simplistic, focusing mainly on the love story of the heroine and lacking in other areas such as political intrigue or moral dilemmas.
One reason could be that he thinks they are too unrealistic. Heroine novels often have elements of fantasy and over - the - top romance, which might not appeal to his more practical or down - to - earth nature.
One possible reason could be a misunderstanding. Maybe the hero misinterprets the heroine's actions or words and lashes out with an insult.
One possible reason could be a misunderstanding. Maybe there was some miscommunication in the past that led the hero to form a negative opinion of the heroine. For example, he might have overheard something that was misinterpreted.
Maybe he has some personal beliefs or values that conflict with the typical themes in heroine novels. For example, he might dislike the often overly romanticized or damsel - in - distress portrayals in those novels.
Maybe she has had some bad experiences related to so - called heroes in real life, which makes her cynical about the idealized heroes in romance novels.
Maybe she's scared of commitment or has trust issues. Or perhaps she feels like the hero is too intense or overwhelming for her.
One possible reason could be that the hero has a bad reputation in the society they live in. Maybe he is known for being a playboy or having a cruel streak, which makes the heroine despise him.
Perhaps the hero hides her out of jealousy or possessiveness. The result might be a lot of drama and misunderstandings before they finally work things out.
Maybe the fanfic often misrepresents the nature or relationship of Bellatrix and Rodolphus. For example, if in the original they are portrayed as very dark and loyal to a certain cause, but fanfic makes them out to be something else entirely, like soft or good - hearted, it could lead to dislike. Also, some people who are die - hard fans of the official story just don't like the idea of others taking creative liberties with their beloved characters.
Another possibility is that he doesn't like how some fanfictions over - sexualize the characters. In some cases, fanfiction can turn into something inappropriate, and Harry, who has a more pure view of his friends and the wizarding world in general, would be disgusted by this. He wants to preserve the integrity of the relationships and the world as he knows it.
One reason could be the inaccurate characterizations. Fanfiction writers might not fully understand the nuances of Nightwing or Batman's personalities, and Nightwing hates seeing a wrong version of them. For instance, if Batman is made too soft or too harsh in a way that doesn't match the established canon.