If the art is so ethical why are description of it so often done in such a bad way?

I suspect that part of the reason is that the first steps that many an aspiring PUA needs to make is to free themselves from emascalating politically correct influences that they have eagerly subjected themselves to. They haven't understood that most of what people say is the right thing to do is, well, not. They cut themselves free from the naive, childish ethical intuitions and rely on raw, stark descriptions of reality for a while. From there they can go ahead and form an adult ethical system that works for them in practice rather than being good for morals in fairy tales.

But then, I don't actually agree that the descriptions are usually bad, at least not in any of the sources that I respect. The two examples that you give ('compliance' and 'time distortion') don't seem remotely unethical to me. That 'baddness' is in this case in the eye of the beholder.