First, to make you prim and proper, a primer: The History of Politcal Correctness.
This link also embeds the HoPC documentary, but acts as a sort of transcript.
Now, watch Bill Whittle expand on this documentary with a passion and contemporary tie-in that will likely leave you stunned.
I subscribed to PJTV when it was still experimental. I hope you consider supporting this wellspring of excellence.
My only question, and a quick Google and Wikipedia scan bore no fruit, is the tie between Saul Alinsky and this Frankfurt School.