I think it was Rick Rubin's influence. The sexism and obnoxious frat boy thing might have been a joke in the beginning....but it wasn't a joke or parody for Rick. And I think they were kinda following his lead. I know their original drummer kate Schellenbach (later co-founded Luscious jackson) had a falling out with them because the line between satire and reality was becoming questionable. They apologized and reconciled with her later on and were generally ashamed for what they became for a few years.

As a sidenote....RIP to MCA. I usually hate when artists get political but he found a way of doing it that just appeared to be so genuine and heartfelt without being self-aggrandizing or opportunistic. This clip is so touching. I love watching him getting ready knowing what he was about to do before talking. Focused:

https://www.youtube.com/watch?v=yT1FT-zXtDw