Political correctness is both simple and benign. It's telling someone who's being a dick (to people who don't deserve it) that they are being a dick. That's all. Yet the response is generally along the lines of, "Boo hoo hoo! I'm so oppressed! I was being a dick, but you called me a dick! Boo hoo hoo! You're worse than Hitler!"
Sack up, dick. You apparently see yourself as mentally tougher than the crybabies who can't handle mean words, but this "poor, poor me" tantrum casts doubt on that, to say the least. You're being a dick. Own it. Otherwise, you're also a pussy.
Political correctness can be tedious at times, but the backlash against it is both tedious and pathetic.
I'm not going to claim to be politically correct, but I hope I never whine about how oppressed I'm being. You know, by those jackbooted thugs with their... disapproving looks and wagging fingers. Or something. What kind of weapon of authority is it that they wield? I forget. Maybe it's too horrifying to remember.
Nerdy notes about the term and its history
If Wikipedia is to be believed, the term was coined at a time when Communist Party members in the U.S.S.R. were being criticized by Socialists for keeping to the "correct" position on political matters "regardless of their moral substance". In the seventies it was picked up in the western world by the New Left as a joking "guard against their own orthodoxy in social change efforts."
In the nineties, conservatives picked up the ball and ran with it. "Political Correctness" is a perfect term to use when you want to paint your opponents as being intolerant. As, sweet irony! "I'm not being intolerant by not tolerating [group]. You're being intolerant by criticizing my intolerance!" It's practically guaranteed to work, not because it makes sense but because it takes the burden of guilt off the shoulders of your ideological followers and places it squarely on anyone who criticizes their philosophy.