There could be several reasons. One is that Frederick might be very attached to the official version of Percy. Fanfiction can be very different in terms of plot, character development, and tone. He may not like the idea of others taking liberties with the character he has a certain perception of. Another reason could be that he has a particular aesthetic or moral view related to the Percy story, and fanfiction often doesn't conform to it. For instance, if he believes that Percy should always be portrayed as a heroic and morally upright character, and some fanfiction shows Percy in a less favorable light, he would disapprove.
Well, it could be that Ron has his own ideas about how Ginny and Harry's relationship should be. Fanfics often take creative liberties and might deviate from what he thinks is the 'right' way for them to be together. He might not like seeing their relationship twisted or fictionalized in ways he doesn't agree with.
Another reason could be that she wants to control the narrative around her works. Fan fiction can spread quickly and widely, and if it contains inaccurate or inappropriate interpretations of her stories, it could potentially damage the reputation of her original works. Also, she may prefer that readers engage with the official versions of her stories rather than fan - made alternatives.
The simplest thing would be for him to just avoid reading those fanfics. If he doesn't like them, he doesn't have to engage with that part of the fandom.
Maybe Frederick has a different view of the original work and thinks fanfiction distorts it. For example, if he is a purist who loves the original Percy story as it is, any fan - made alterations in the fanfiction might be off - putting to him.
Maybe Percy just doesn't like the complexity and strategy involved in poker. In fanfiction, authors often create characters with specific personalities and interests, and perhaps poker simply doesn't fit into Percy's character profile.
Maybe he doesn't like how others might distort their relationship in fanfiction. He values their real relationship and the story as it is, so seeing different interpretations in fanfiction could be off - putting.
In some fanfictions, Percy's lack of care could be due to a change in his personality after a major event. For example, if he's been betrayed by someone close to him. He might feel that the world of demigods is not what he thought it was. So, he starts to distance himself and act as if he doesn't care about the things that used to matter to him, like protecting Camp Half - Blood or going on quests. This can add an interesting twist to the fanfiction's plot.
Maybe he feels that fanfiction often distorts the real relationship between them. He might prefer their relationship as it is in the original story, without all the made - up scenarios in fanfiction.
Adventure is likely to be a theme too. Maybe they go on some sort of journey together, facing challenges along the way. For example, they could be exploring a mysterious place and relying on each other's skills to get through it. It could also involve them learning from each other. Frederick might have certain knowledge or abilities that Percy doesn't and vice versa. So, through their meetings, they grow as characters. And of course, there could be elements of loyalty in the stories, standing by each other in difficult situations.