Fanfiction starting with Harry Potter could be due to several reasons. Maybe it's the rich magical world that offers endless possibilities for new stories. Or, it could be the strong fan base and the desire to explore different scenarios for the characters.
It could be that Harry reads Harry Potter fanfiction to feel more connected to his fans. By reading what they write, he gets a sense of how they view him and his friends. He might also find comfort in the fact that his story has inspired so many people to create their own tales within the same universe. Fanfiction can be a form of flattery, and Harry might enjoy seeing how much his story has captured the imaginations of others.
It could be due to the trauma he has experienced. Losing friends and facing Voldemort multiple times has surely left deep scars. Isolating himself might be his way of dealing with the post - trauma stress. He needs time alone to heal and come to terms with everything that has happened.
Also, legal issues play a role. There may be laws and regulations regarding intellectual property that the 'Harry Potter' owners are following. By banning fanfiction, they are ensuring that their intellectual property is protected and that no one is misusing or misappropriating the concepts, characters, and world they have created.
Well, in some cases, the quality of fanfiction varies greatly. There might be a lot of poorly written fanfictions out there that use the Harry Potter name just for popularity. These might have bad grammar, inconsistent characterizations, and illogical plots, which can make the whole idea of fanfiction based on Harry Potter seem annoying.
It could be that someone did something really wrong and Harry needed to express his strong feelings in a very public and intense way. Howlers are notorious for being attention-grabbing and forceful.
Well, Harry Potter has his own real and complex life. He has grown up in a difficult situation, facing challenges and traumas. Fanfiction is a concept from our world, outside of his own experiences. He's more concerned with the things that directly impact him, like the Triwizard Tournament, his relationship with Dumbledore, and the mystery of his parents' death. Fanfiction doesn't have a place in his immediate concerns. He's constantly in a battle against the forces of evil, and that takes up all his attention.
In some fanfictions, Harry Potter might use a cane for various reasons. One could be that he has suffered an injury during one of his many battles, perhaps a leg injury that didn't heal properly. Another reason could be that it's a magical cane with special powers, like it can be used to channel his magic in a more focused way or it has some sort of defensive or offensive capabilities.
Because he lives in his own world. Fanfiction is something made by fans in our world, not in his magical world. He has no way to know about it.
One reason could be the large fan base of Harry Potter. Fans are more likely to write about him in relation to other characters like Narcissa. Since Harry has so many different aspects to his character, such as his courage and his mysterious connection to Voldemort, it gives a lot of room for creativity when paired with Narcissa. He can be the hero who changes Narcissa's view, or he could be in a conflict with her, which makes for engaging fanfiction.
He could be looking for different perspectives. Fanfiction often has unique takes on the characters and events. For instance, some fanfictions might focus on the backstories of minor characters like Neville's family history in more detail. So, it gives him a chance to see the wizarding world from different angles.