I think unions are fundamentally for collective bargaining against consolidated powers typically capital. Police unions in the USA have been bastardized to favor their own and resisting change to a power structure that helps them, Aka losing class consciousness.

Let’s say the police departments started mistreating individual cops, overworking them and sending them into dangerous situations without proper training (hint: as they do currently), how so the individuals being mistreated fight back?

What I see in America is a concerted effort to construct a Us vs Them narrative in the police force. This includes dehumanizing the “policed” and protecting their own at all costs. This is essentially losing class consciousness, where a fellow working person is seen as fundamentally evil, and the real reason its so bad for cops.