Alot of it? Because people don't really look into it beyond what they're told. Not to mention they think the barest mention of them is grounds for witch burning. Doesn't help that media presents it in the worst way possible pretty much every time and in a really stupid fashion to boot.
The funny part is, the baseline classes honestly are healthy for pretty much anyone, all about projecting confidence and finding something you can do to make people go "OOOOO SHINY" that most other people can't do as well, if at all. Pretty harmless honestly.
It's the later stuff that can be destructive and very unhealthy however. Manipulation is something everyone does when they start dating, anybody that says otherwise is either lying to you, or has known who they're dating for years before they start that part.
Honestly most of them are harmless, abrasive and maybe act a bit like children when they don't get their way when they use all their toys, sure, but I doubt many more than the people in charge would act on anything, and even then, PUA is about not really having to use physical force to do anything.
But hey, I've got an overall positive view of it considering I've got a roommate that met her girlfriend because of going to a couple classes(*gasp* only men can be PUA's right?). So feel free to bring out your pitchforks and kindling. Or ignore what I'm saying, whatever.