Yes BUT...there is a difference between platonic socialization and flirting/courtship. Some people can flirt naturally. Some people have to learn it. Some people can't turn it off. Which is why blanket advice for how to treat other people isn't particularly helpful.
So yes, most PUAs are creepy and gross. But also, for those who don't understand flirting innately, it's not like there are a ton of obvious reputable resources available on how to do it. And some PUAs do explain some of the key bits of psychology behind flirting. Things like tension and release, light teasing, managing eye contact, reading body language, escalating physical touch...things that you should be approaching differently if you're trying to flirt with someone vs being friendly. Things that people expect you to do if you're interested in them, that aren't inherently obvious.
And I say this as an ASD guy who confused a LOT of girls in high school by not courting them like I was "supposed" to, then started doing real research in my 20s into things like body language, flirting styles, love languages, attachment styles, etc, and coming to a lot of epiphanies about how stupid I had been, and am now in my 30s reasonably successful at dating.
For those curious on some actual resources, The Definitive Book of Body Language and The Five Flirting Styles are good places to start on learning the differences between platonic and romantic socialization!___