Like "redneck" and "hick" and "white trash"?

That's the other thing I think people are reacting to. There's a double standard where it's okay to slur rural white Americans but nobody else.

IMHO it's about classism as opposed to racism. Racism is taboo in American discourse but classism and urban elitism (placeism?) are not.

Maybe the answer is to define PC as you do and extend it to cover classism, placeism, and reverse stereotyping. Maybe it should just be taboo to be an asshole.