Obviously you haven't been alive long enough to really sample the varieties of "PC" thinking. I remember the first months (years?) after 9/11 where it was extremely un-"PC" to oppose war in Afghanistan and Iraq, or point out that US foreign policy might have had a role in fomenting terrorism. That would be right-wing "political correctness".
Of course I have also experience the type of "PC"ness in some obscure left-wing subscultures where anyone who referred to a 12-year-old girl as a "girl" and not a "woman" was considered sexist, ageist, etc.
When people attempt to frame Obamacare as an intrusion of socialism/ communism, they are employing "political correctness." It is extremely politically incorrect to actually be a communist in American society.
Complaining about political correctness is politically correct. There is not a single group of any mainstream political persuasion that has not found it, at some point, opportune to announce its lack of political correctness. Everybody, at some point, likes to be seen as defiant of "political correctness." It is a vapid rhetorical bugbear.