Is there a limit to political correctness in the performing arts?

Does political correctness have limits? I am over at a neighbor’s house and he is watching a DVD of Chris Rock, it had to be made within the last year because part of the gags were of Michael Jackson’s death. Frequently through the routine he would toss out the ‘N’ word. It was a mixed crowd but I got to thinking, what if it were Paula Poundstone, Josh Blue, Andrew Dice Clay, or George Carlin had a routine laces with the ‘N’ word, would people see the performance or them differently? And if they would how or why is it OK for Chris to use it without penalty?