It is hard to get good basic information about a lot of left-wing movements. Long ago when I was reading National Review Jonah Goldberg wrote something about Antonio Gramsci, to the effect that he changed the proletariat in Marxism from industrial workers- in the era of Marx skilled people we would consider middle-class- to criminals and other social deviants. But if you look up Gramsci on the web, you get a bunch of impenetrable Marxist jargon.
The Frankfurt School- a group of German Jewish intellectuals who came to the US in the 30’s- get a lot of blame for trashing social and sexual norms. But again the readily available information doesn’t give you a lot of useful knowledge. I think I got this from Occidental Observer- a critique of the genuinely foul film “Pleasantville”- illustrating how the Hollywood Jews inspired by the Frankfurt School attacked the traditional social order.
Margaret Mead- an Espicopalian as well as a cheerleader for teen sex- was indeed the student of atheist Jew Franz Boaz. But as we see from “Degenerate Moderns” by E. Michael Jones, this process of undermining traditional values was already underway in England, by upper-class communist homosexuals. This general line of thinking- finding the authentic in the childlike and the primitive- was underway even earlier with the educational reformer John Dewey. Not to mention the corrosive forces of German Romanticism.
You could be rude and say Jews were late to the game, but I think it is more of the case of waiting to see if the Next Big Thing is going to take off.
Freud gets a lot of blame as well. Whether you think Freud was a complete fraud, per Jeffrey Masson, or had some interesting insights on human behavior, he was quite conservative. He did indeed believe humans were driven by the basest urges, to kill or have sex with their parents, but believed psychological health was preserved by channeling these urges into marriage, family life and work.