Maybe because in those fanfictions, Hermione's bossy character is over - emphasized. Harry might feel like it doesn't stay true to their real friendship dynamic in the original series.
It could be that Harry in the fanfiction is always being pushed around by Hermione in a way that he doesn't like. In the real story, they are equals and friends, but the fanfiction makes it seem like Hermione is always in control, which might be tiring for Harry.
The writers could try to show a more nuanced relationship between Harry and Hermione. For example, show how Harry stands up to Hermione's bossiness in a friendly way, which adds more depth to their relationship.
Maybe he's read too much of it and found the plots repetitive. Fanfictions often follow certain patterns, and after a while, it can get boring.
Some might not like Hermione's bossy attitude in fanfiction because it can overshadow other aspects of her character. In fanfiction, people often look for more nuanced and relatable traits. Her bossiness might seem too dominant and lessens the charm that other softer or more complex traits could bring.
Some writers might create such fanfiction for the shock value. They want to break the established strong friendship in the original series to get readers' attention.
Well, it might be part of a fantasy world created by the author where unusual circumstances bring Harry and petrified Hermione together. Maybe it's to create tension or drive the story in an unexpected direction.
One common theme is the aftermath of battle. After all the fighting against Voldemort and his Death Eaters, the characters, especially Harry, are often depicted as physically and mentally exhausted. They have to deal with the trauma of what they've been through.
One reason could be his status as the main character in the original series. He is the 'Chosen One', so fanfiction writers may be more inclined to center their stories around him.
It might be that Harry Potter values the authenticity of their story. Fanfiction can be all over the place with different plotlines and characterizations. He may feel that the fan - made stories about Hermione don't do justice to their real - life (in the wizarding world) experiences together. He's used to their real interactions and growth, and fanfiction might seem like a strange and wrong version of that to him.
One great 'Harry Potter' tired fanfiction is 'The Weary Hero's Return'. It shows Harry after all the battles, just completely drained and trying to find normalcy. It really delves into his mental and physical exhaustion in a believable way.
Maybe Harry is tired of the constant danger and battles. He might decide to take a break from the wizarding world, perhaps go into hiding in a Muggle village to find some peace.