Nicely done. According to this, the Magna Carta of Political Correctness is the 1965 essay by Herbert Marcuse, Repressive Tolerance. I guess I have to read it, however distasteful that may be.
So it is said that if you know your enemies and know yourself, you can win a thousand battles without a single loss.
If you only know yourself, but not your opponent, you may win or may lose.
If you know neither yourself nor your enemy, you will always endanger yourself.
Sun Tzu, of course.