Maybe in the fanfiction, Harry has some bad experiences at Hogwarts before. For example, he might have been bullied by some students or had a really tough time with certain teachers. So he doesn't want to go back.
It could be that in this fanfiction, Harry has found a new place outside of Hogwarts that he feels more comfortable in. He might have made new friends or discovered new magic that he can't practice at Hogwarts, so he doesn't want to go there.
One possible reason could be that in the fanfiction, his family might have decided to keep him away from the wizarding world for his safety. Maybe they feared the dark forces at Hogwarts, like Voldemort's followers.
In this fanfiction, it could be that Harry has a falling - out with Dumbledore or other important figures at Hogwarts. This makes him feel unwelcome or betrayed, leading him to choose not to go to Hogwarts and seek another path in the magical world.
The plot might develop with Harry exploring the non - Hogwarts magical world. He could meet new characters who introduce him to different magical cultures and spells.
Well, it could be that Harry has such a personal and intense experience of Hogwarts that he doesn't like how fanfiction can be so varied and not always in line with his own memories and feelings. He might feel that the real Hogwarts story is already perfect as it is, and fanfiction is just an unnecessary addition that doesn't capture the essence. For example, he might not like how some fanfictions change the relationships between characters or create out - of - character scenarios for his friends at Hogwarts.
One possibility could be that he discovers a different magical school. Maybe there's a hidden school in the Muggle world that he stumbles upon. It could have its own unique curriculum and culture. He might make new friends there and learn magic in a completely different way compared to how it's taught at Hogwarts.
She could end up in a non - magical educational institution for a while. During this time, she might try to apply her love for learning in a different context, like studying advanced sciences. However, her magical abilities would still be there, and she could end up using them in unique ways, perhaps accidentally, which could draw the attention of the wizarding world and lead to her being brought into the magical community in a very different way than going to Hogwarts.
In some fanfictions, the author might have made Harry not go to the Yule Ball because they want to create a different plotline. Perhaps they are focusing on Harry's independent study or some secret mission that he has to undertake during the time of the ball. So, instead of going to the ball like in the original story, he is off doing something else more important in this fan - created scenario.