Why is he part of Salem's group?

From what we've learned, he has an okay life outside. Sure, his sister died on a mission approved by Ozpin some years ago. But other families lost their members in similar, if not the exact same ways. And Oscar's questions show that he, a kid not much older than Ruby, understands the life of a Huntsman or Huntress better than Hazel in some aspects.

So Hazel has a personal stake in the fight against Ozpin and his 'reign'. But so do others. And outside the Vale Council being dicks to him, we don't really see anyone go after him. Ozpin isn't the greatest human being ever, big whoop. Ya know what some people still protest today?

Their sons and daughters going off to join any military organization when they're 20 years old. And that's dumb in its own right, but not why I'm here. Hazel's sister was probably the normal Beacon entering age of 17 or so. And she died on a mission. Not a scenario unique to you, Hazel my boy.

So why are you on Salem's team? You could have gone at this from... virtually any other angle, and we'd still call you a little dumb but not the braindead moron I currently think you are.