I'd say the best way to sum up political correctness in my view is it's a sometimes clumsy manner to try to encourage equality. I'm one of those people who is a strong, and a somewhat fanatical, believer in intent and context. A lot of people, from time to time, make statements that could be seen as racist, sexist or homophobic. Hell, I do so myself. However, because I've made a few jokes about the holocaust or about AIDS doesn't mean I'm anti-Semitism or homophobic. My sometimes offensive sense of humour does not show my views on equality, contrary to some popular belief.
What I'm not saying is all jokes are free from moral judging. The type of laughter at "god damn you're right, that social group is incompetent" or something along those line is something I dub as "gritting teeth laughter". The type of thing some people laugh at out of hatred of that group. An example of what I mean is George Carlin and Roy "Chubby" Brown. George Carlin goes on wild rants about how there is no God a lot, and how religion is false, however this does not mean he dislikes believers. Roy "Chubby" Brown, you can pretty much guarantee that 90% of people in the venue hates foreigners, the 10% are made up of people dragged along, people who don't listen to many comedians and the staff at the venue.
Personally, I believe people should assess the likelihood that the joke was "gritting teeth laughter" before judging. If it was just some stupid "get in the kitchen" joke, then it's meant to be harmless. If it's someone saying something along the lines of "sexual harassment doesn't exist" or something like Jeff Dunham (which involves getting the irrational fear society has of Muslims and uses that to make offensive jokes about the Islam religion), then feel free to rip into them.
Oh, and I'd recommend people to check out Stewart Lee's political correctness stand up. In case people are concerned he's just going to say "political correctness is shit", it's more him ripping into people saying "it's political correctness gone mad".