Another possible reason is that Percy is following a prophecy or a higher purpose. The gods or some other powerful entities might have given him a task to keep the peace among the camps. He knows that if the camps fight, it could disrupt the balance in the world of the fanfiction. So, in order to fulfill this task and maintain the order, he takes steps to stop the camps from fighting.
In the fanfiction, Percy might use his leadership skills. He could talk to the leaders of each camp, explaining the futility of fighting and the greater threats they might face together. His reputation as a hero could also play a role in making the camps listen to him.
The food. Often, fantasy camps have a lot of indulgent food options. Like rich, creamy pasta dishes, lots of cheese, and big slices of cake. It's hard to resist these when they are available all the time.
Some fanfiction writers may have a different vision for Harry Potter's character. They might see him as more of a diplomat or a healer within the wizarding world, rather than a fighter. So, they write stories that reflect this different view of the character, where he uses his wits and other skills rather than engaging in physical or magical combat.
Perhaps Draco has been bullying some of Percy's friends or younger students that Percy feels responsible for. In fanfiction, the relationships can be tweaked a bit. Percy might be more hot - headed in some versions and not put up with Draco's pure - blood supremacist attitude towards those he deems as 'lesser' students. So he sends the Howler as a strong warning.
One reason could be to avoid a dangerous prophecy that they believe the camp can't protect them from. In some fanfictions, they might think that by running away, they can face the threat on their own terms.
It could be because Percy is different. If he comes from a different background or has a unique personality trait, the bullies might target him. In the fanfiction, if Percy is from a different race or has an unusual way of speaking, the bullies might pick on him for not being like them.
One reason could be his regret over his past actions. For example, when he distanced himself from his family to pursue his career at the Ministry. He might realize later how wrong he was and cry out of remorse.
Maybe it's part of a plot to have Percy gain some sort of power or knowledge. In many fictional stories, a character has to go through great pain and suffering before emerging stronger or wiser. The torture in Tartarus could be a way to set up this transformation for Percy.
Perhaps Percy doesn't have the right group of friends to play poker with. If his friends are all into different kinds of activities, like studying magic or fighting monsters, there may not be anyone around to initiate a poker game. So, he just never gets into it.
One reason could be to create drama. Writers often like to shake things up in the relationships of well - known characters. Another might be to explore different sides of Zoe's character, perhaps showing her as more complex or flawed than she appears in the original work.