Everyone that tries to exert any authority over anyone sucks. There can (sometimes) be slight mitigation for parents, and (more rarely) even teachers. But they all suck.
Generally true. Though there are exceptions.
One of the bosses I had would always go to bat for his employees. He was an excellent reference that helped land me my current job, and he helped me out outside work more than once. Dude's solid.
Like cops, the decent ones are rare in a sea of assholes.