Eh, they are probably just focusing on what they can change. Changing managers is a hassle with a good chance of getting it wrong. I can clam up, say nothing, and work on other work during retro very easily.
That is normal management, dismissing it as "bad management" makes it sound as if it isn't widespread and that we shouldn't base our practices around working with such managers. Managers who don't penalize you for being negative are rare, even those who say they don't typically do it anyway.