Let's look at fat people. Liberals decided it was "kinder" and "more sensitive" to call fat people "weight challenged." Truth is, it is less kind and less sensitive. Think about it - if you call fatso "weight challenged" do you really think he does not know you are calling him fat, but hiding it in nice words so you don't have the guilt associated with calling him fat? He knows! And it insults him even more than if you had been up front and called him fat.
Political correctness is like shooting at people while you hide in the bushes.
Liberals are always looking for ways to escape responsibility, and do whatever they want without guilt. That is why liberals strongly support abortion - the politically correct word is "choice". They conveniently overlook the fact that it has nothing to do with choice, since the choices were already made - the choice to sleep with someone. The choice of not employing protection. So, abortion is nothing more than escaping the responsibility for choices already made. And again, political correct verbiage colors the issue - it is simply "choice" and no one can argue that people deserve a choice! It changes the language to change the conversation.
It is politically correct to not allow Christians to employ any public displays, in spite of the 1st Amendment which clearly states we all have the right to practice our religions without government intervention or restriction. Liberals are using PC to weaken the power that Christianity holds, because it is Christianity that provides a moral fabric - one that many committed liberals want nothing to do with. As long as Christianity has a hold on America, drugs will never be legalized. Man-Boy Love will never be legalized. All the sins will become OK once Christianity is gone, which relieves them of guilt.
Christianity requires personal responsibility, and lays guilt upon those who do wrong. Most liberals want nothing to do with personal responsibility or guilt. That is why they use PC to weaken Christianity's hold on America.
Political correctness keeps people from telling the truth. Mitt Romney wants to use PC to make sure he does not offend the Palestinians. Newt Gingrich says "to Hell with PC - let's tell the world that Palestinians are terrorists and an invented people (which they are, in fact). But all the establishment GOP, the liberals and the media think Gingrich said a bad thing - they have all been conned by liberals into believing PC is good, truth bad.
Reagan believed PC was wrong, truth good. Against all advice from all sides, he called Russia an "evil empire" and told Gorbachev to "tear down this wall". Had he chosen the PC manners of Romney or any of the others, the wall would still be standing.
Political correctness is a sign of weakness and always morally wrong. Always. Because it is diametrically opposed to MORAL correctness.