Political correctness is vital to the Left, because disqualification is the only form of argument they have left to them:
This ubiquity of “check your privilege” suggests that political correctness is now entering a second generation and gaining a second wind. While political correctness previously concentrated on race and gender, the new focus on inequality seems to have emboldened the campus left to put class back on the list of identity politics. Of course, using the phrase “check your privilege” to cut off debate on campus is not nearly as destructive as what communists did to people who were from the “wrong” class. Many children of privilege then were sent to reeducation camps to reflect or were even silenced never to speak again. But it stems from the same impulse to replace reason with power.
This new form of an old disorder also shows that despite the orthodoxy on many campuses many left-liberals remain very afraid of classical liberal and conservative dissent. Just as students who protested Condi Rice’s prospective graduation speech at Rutgers showed strength in numbers but weakness in intellectual confidence, so do those who parrot this new campus slogan. If your underlying argument is flawed, you do need a force other than logic and evidence to sustain your position. Political correctness is an admission of intellectual frailty.
My privilege is my intelligence. It’s hardly my fault that the other side correctly sees itself as being disadvantaged and underprivileged.