I remember a presentation I saw in high school one of my classmates gave on Mauritania, in which they declared 1/3 of the population was of Arabic decent, 1/3 Moorish, and another third was "African-American"...
"Black" isn't politically incorrect. And neither is Caucasian technically correct (Caucasian = from the Caucasus, an area between the Caspian and the Black sea including Albania, Georgia, Azerbaijan, etc).
I just tell people I'm Native American, which most people balk at. But really, my family has been here 4 generations at the low end, and too many generations to count at the high end. I hold no cultural ties to England, Germany, Scotland, etc. I was born here, I am an American, I can't get any more native than that. And believe it or not, many First Nation or "Indian" people find the term Native American offensive, to them we're the Americans, because we destroyed their nations to make America. To some of them, the idea of being called American in any context is offensive and grossly inaccurate. There was no "America" before the Europeans came here.
Political correctness has gone way overboard, but to imply it's "completely useless", like most absolute statements, is a bit overboard. The expectation that politicians and our government exercise political correctness is what prevents our government from (overtly) playing off racial tensions and ingrained primordial sentiment, a problem many nations have had that result in ethnic violence (Rwanda, Yugoslavia, Germany) and salient ethnic tension (India, Belgium Canada, lots of others). Political correctness is the part of our freedom, believe it or not, which allows a Muslim to be angry when he is scrutinized at an airport, and allows a black person to be offended when the security officers follow him around in the store. Political correctness takes away some of the ethnic tension in America that, believe it or not, is quite lower than many other nations, even those that we could consider civilized.
It's a personal choice. Yes, you're allowed to call mental challenged people "retarded", and your allowed to call homosexuals "queers", this is America and unlike many other countries you're allowed to say (mostly) anything you want. And political correctness is never going to be legally required in this country, so there's really nothing to worry about except the fact that being PC is, in some limited circles, becoming socially expected (there are still much larger circles I believe that are fighting against political correctness). Basically, if you have it good enough to just be able to complain about using good manners to be acceptable (since it's not legally required), you need to stop BAWWWing and put a little perspective on things.