It could be that in the fanfiction world, Bella's mother has made some bad decisions in the past that directly affected Bella negatively. Perhaps she abandoned Bella at a crucial time, which led to Bella's hatred.
Bella's hatred could also lead to her making rash decisions. For example, she might get involved with the wrong crowd or engage in self - destructive behavior just to spite her mother. And this could further complicate the story in the fanfiction.
It could be that the fanfiction writer took a different approach to the story. In some fanfictions, the Cullens could be involved in situations that go against what Bella stands for. Perhaps they are written to be more secretive and untrustworthy, leading to Bella's hatred.
Well, it could be that the plotlines in the Sam fanfiction are just not to Bella's taste. She might prefer different types of stories, and the ones about Sam are often full of elements she doesn't like, such as certain relationships or events that are depicted in the fanfiction.
One possible reason could be that she discovers some dark secrets about the Cullens. Maybe she finds out they have been lying to her about their true nature in a more malicious way than in the original story. Another reason might be that she feels threatened by their vampire powers. If they accidentally or purposefully use their powers around her in a menacing way, it could make her feel scared and turn that fear into hatred.
If Paul hates Bella fanfiction, he can simply avoid reading it. There are plenty of other types of literature or fan - made works out there that he might enjoy more.
One common theme could be betrayal. Maybe in these stories Edward does something that makes Bella lose trust in him and thus start to hate him. For example, he might lie about something important.
If it really bothers her, she could try to find a community or group of people who also dislike Bella fanfiction and discuss her feelings with them. This way, she might feel less alone in her dislike and could even get some ideas on how to deal with it better. For example, they could share tips on how to filter out Bella fanfiction when browsing for new stories.
It also makes her more patient. Vampire children, or even adult vampires she might be mothering in the fanfiction, can be difficult to understand and manage. Bella has to learn to be patient with their different ways of thinking and behaving. For example, if they don't understand human emotions like love in the same way, she has to patiently explain it to them.