Political correctness (n.) is a desperate reaction. Its proponents know they cannot solve the real problem of actual social relationships with the other so they escape into controlling how we speak about it.
Political correctness (n.) is a kind of distancing effect. It keeps the other at the proper distance and doesn't allow them to come to close to me (picture an upperclass white couple among lower class blacks telling dirty jokes). Tolerance often means intolerance for the actual other. They accept the other, in it is the purified other.
Political correctness (n.) is, in fact, a kind of successful racism. It reproduces all the former prejudices but with a very soft point apparently respecting the other. Tolerance is a false notion that keeps the other at a distance.
Political correctness (n.) is problematic because the way it is approaches is that instead of resolving it the predominant effect is just to keep it under check and allowing the true problem, racism, sexism, to survive in a more covered up version and so on and so on.
Political correctness (n.) is wrongheaded because it ossifies, or fixes hate. It enables you to repress your hatreds, but those hatreds are still there.
Political correctness (n.) is wrongheaded because it tries to regulate or legalize what should be the spontaneous ethical substance.