Hunter is not likable, nor is he written as such. He’s deliberately depicted as a product of his upbringing, and “Raised by Wolves” shows how his cloistered life has shut him off from the humanity of those outside his religious sphere. As the son of a high-ranking Mithraic, he’s cocky about his social status, particularly when it comes to the other children, and incompetent when it comes to labor.
It’s clear that Hunter feels predestined to grow up pampered and respected like other Mithraic clerics. Like many of the kids, Hunter largely had to grow up on his own, and he deserves a thwack on the back of his head for his sanctimonious nature and the way he bullies Campion and others. However, his abrasiveness does not come from nowhere. His dissatisfaction is realistic for a kid in his surreal situation.
By season 2, Hunter has humbled himself enough to question things. Mostly, he’s resigned to his circumstances, later announcing to Father that he plans to move out and deal with life in his own way. He remains an insensitive brother, but he has slightly better intentions.