It's Politically Incorrect, so it Must be Funny is the motto of militant twits who try their damndest not to be Politically Correct. What they don't realize, though, is that by hailing something as good simply for the fact that it's politically incorrect, they're just being as correct as a person who would be offended by the same thing.
The first instance of It's Politically Incorrect, so it Must be Funny occurred when Greek Philosophers Chrysippus and Frank were walking around and saw a donkey eating figs. At the time, a donkey eating figs was considered to be a harsh satire on snooty uptight Philosophers. Frank contended that it wasn't really that funny. Chrysippus derided Frank for being so easily offended, and then to prove his point laughed so hard at the donkey eating figs that he died.
Frank would continue telling people "it's a donkey eating figs, what the fuck's so funny?" even to his deathbed, and every time he would, surely there'd be some Politically Correct douchebag next to him telling him to ease up and not be offended so easily.
At the same time in Asia, Pene y Pelotas, the famous historian and revolutionary, was studying balls when Marco Polo reared his Iti ass. Marco Polo laughed at Pene's tiny penis and Pene said that it was politacally incorrect to laugh at an Asian for having a small dick. Therefore, this is funny.
edit Boom of Popularity in the 2000's
With the sudden explosion in the PC-Fag population, soon followed an equally large explosion in the Un-PC-Fag population. The PC-Fags would insist that a comedian like Larry the Cable Guy was offensive to minorities. Un-PC-Fags would insist that the PC-Fags stop being so offended, and then hail Larry the Cable Guy as the comedic mastermind of our generation. Meanwhile, all the sensible people came to a quiet conclusion that he wasn't really all that funny, though they guess some of his material was all right, and that if anything they were offended that the Un-PC-Fags made him so goddamn popular when he has no fucking right to be popular. I mean seriously, he's just a stupid fucking shock comedian, does Mike Birbiglia really not deserve the attention Larry the Cable Guy gets? Mitch Hedberg had to fucking die before he got half that recognition! And Mitch Hedberg is ten times as funny as Larry the Cable Guy, it's not even a debate, it's just true. Seriously, all of you can fucking bite me, I hate you.
While PC-Fags and Un-PC-Fags would at first appear to be polar opposites, they're actually the same exact thing. PC-Fags immediately call something worthless due to its possibly offensive nature, and un-PC-Fags immediately call something awesome due to its possible offensive nature. But neither actually thinks about whether or not the actual content of it is funny. So they both suck.