Of course, people who like to say offensively rude things about subordinated groups nowadays react to complaints about their bad manners by charging their critics with enforcing “political correctness.” But that doesn’t make the attitude that searches relentlessly for evidence of thoughtcrime in every deviation from the currently approved vocabulary any less a threat to sane thought and civil discourse.
Give someone a hard time for saying “kike”? Sure. Gently tell someone who innocently uses “Jew him down” as a synonym for “bargain hard” that Jews find that locution offensive? Absolutely. Insist on saying “person of the Jewish faith” instead of “Jew”? Later for that.
The problem of substance, as opposed to language, is a harder one, as Glenn Loury pointed out in a brilliant essay that doesn’t seem to be on line. But the instinct to attack people who say things you disagree with instead of arguing with them is one to be kept in check.
Naturally, the excesses of political correctness are always easier to spot in the behavior of the other side of any debate. Motes and beams.