It could be that the writer has received feedback from readers or has their own self - reflection and realizes that the Stiles - Scott relationship has run its course in the fanfiction. They want to create more complex and independent storylines for Stiles, and this statement is a way to start that process. This allows for new character growth, different types of conflicts, and exploration of other aspects of the fictional world without the constraints of the Stiles - Scott relationship.
In the world of this fanfiction, 'Stiles is done with Scott' might imply that Stiles has outgrown his connection with Scott in the narrative. It could be because the writer wants to explore new story arcs for Stiles that don't involve Scott. Maybe Stiles has new goals or relationships that are more interesting to the writer, so he's finished with the part of the story that focuses on Scott.
It could be that the author of the fanfiction wants to create some conflict. Stiles might hate Scott because Scott has something that Stiles envies, like popularity or a special ability that seems to overshadow Stiles. So, the author uses this emotion to drive the plot and make the story more interesting.
It becomes strained. Trust is broken, and Stiles may start to distance himself from Scott. He might not believe in Scott's words or actions anymore, and there will be a lot of tension between them.
One reason could be that they feel the official Harry Potter story has a defined end, and the fighting in fanfiction is just over - done. They want to focus on the original tale's conclusion.
One reason could be to explore a unique power combination. Naruto is known for his own powerful jutsu like the Rasengan, and combining it with the Susanoo, which is a very powerful Uchiha ability, makes for an exciting and fresh concept in the Naruto universe.
One reason could be to explore a different side of the pokemon universe. Usually, pokemon stories focus on the journey and battles, but a 'quit' fanfiction can show the aftermath or the reasons behind leaving that world. It could also be a way for the writer to express their own feelings about giving up on something they once loved, using the pokemon world as a metaphor.
Well, loyalty is a big theme. In many fanfictions, Scott and Stiles' loyalty to each other is unwavering, and they would do anything to protect one another. Also, growth is a theme. We see them grow as individuals and as a duo, learning from their experiences in the fanfiction world. For example, they might learn better ways to handle the challenges that come with their supernatural lives.
Often, these fanfictions explore the deep emotional bond between Stiles and Scott. They might focus on their friendship and how it could potentially turn into something more. For example, there could be stories where Stiles realizes his love for Scott through a series of shared adventures and dangerous situations.
The story could start with Stiles being really confused and scared about what's happening to him. He might try to hide it from his friends at first, thinking he can handle it on his own.
If Stiles were bitten instead of Scott, it would change the entire plot of the story. Stiles is a very different character from Scott. He's more impulsive in his thinking at times. So, when he gets bitten, he might not immediately accept the situation. He could go through a phase of denial, which could put him in danger. His friends would have to work extra hard to convince him to embrace his new identity. And his relationship with Derek might be really interesting, as Derek would have to deal with a much more talkative and inquisitive new werewolf.