If Ezra were to hate fanfiction, it could be because he values the purity of his own story and the official Star Wars narrative. He might see fanfiction as a distortion of what he and his friends have actually been through.
Maybe some writers create Ezra in a way that doesn't align with how fans view his character in 'Star Wars Rebels'. They might distort his personality, backstory or relationships, which makes some fans dislike that kind of fanfiction.
Poorly written storylines can also be a factor. If the fanfiction about Ezra has a convoluted or uninteresting plot that doesn't do justice to his character, like a plot that has him constantly making stupid decisions without any growth or learning, it will be hated by fans. The essence of Ezra's character in 'Star Wars Rebels' is his growth and development, and if that's not respected in the fanfiction, it's bound to be disliked.
One possible reason could be that he was poisoned. Maybe he ate something given to him by an enemy who wanted to incapacitate him. In the Star Wars universe, there are many strange substances that could cause such a reaction.
One reason could be homesickness. Ezra left his home planet at a young age, and in some fanfictions, this longing for home can resurface strongly, leading to him crying.
There's no official statement in the Star Wars Rebels canon that Ezra hates fanfiction. Since fanfiction is a creation by the fans outside the official story, it's not something that's directly addressed in the show regarding Ezra's feelings. So, we can't really say he hates it based on the given source material.
One reason could be jealousy. Another character might be jealous of Ezra's connection to the Force or his growing influence among the rebels.
Perhaps in the fanfiction, the Empire discovers a connection between Ezra and Revan and tries to use it against them. They create a false prophecy that says Ezra will become like Revan and bring destruction. Ezra has to prove that he is different and that he will use Revan's story as a guide to bring peace and justice, not chaos.
He could be kidnapped by a group of pirates who mistake him for someone else. These pirates are known for their ruthlessness. The rebels would need to negotiate with other pirate groups to get information about Ezra's whereabouts. It would be a story full of danger and unexpected alliances.
The plot could be that Ezra loses his lightsaber in a skirmish with the Empire. He then embarks on a dangerous mission to retrieve it from an Imperial stronghold. Along the way, he teams up with some unlikely allies who help him infiltrate the base and get his lightsaber back.
Meeting a powerful dark side entity that can manipulate their minds. This entity could make them see their worst nightmares as if they were real. For Kanan, it might be the fall of all his friends and the destruction of the Rebellion. For Ezra, it could be the death of his family all over again. They have to fight against this mental intrusion and their own fear.