I'm respectful of other people out of a desire to be a decent human being rather than because I have "a loathing for common people" or wish to gain some sort of social currency.
I'm having a hard time formulating reasons why people would get so psychotically upset about what used to be considered just good manners unless they're both entirely devoid of empathy themselves, and threatened by people who do experience empathy.
If PC means not using racial slurs to people's faces, then I definitely agree with you.
If PC means that academic freedom and scientific research needs to be subordinated to 'social justice' goals, or that some research areas are 'off limits', then I don't agree.
It really depends on the definition.
Both is wrong, and demonstrably so. Political correctness is mostly not about avoiding to stir up racial hatred, but rather to avoid offending people. Political correctness is not about avoiding topics, that would be called a "tabu".
Anyway, political correctness does not infringe on free speech. Generally it is not enforced by the state, and it requires a sort of consensus in some small or large fragment of society.
The consequences of breaking political correctness are entirely within free speech also. If you use a racial slur, it's not infringing on your free spech for others to call you a racist or stupid or worse. People might also infer other attributes or opinions if you frequently use the word "nigger", for example, and they may be wrong about your support for Ku klux clan, but they are not infringing on your free speech.
If privately or publicly owned publications don't want to publish texts that offend minorities, they don't need to publish it. Again, not infringing free speech. You are free to find a publication or medium that shares your world view.
Free speech does not mean you can say whatever you want without consequences.
The point about how not everyone can hold the high moral ground relative to everyone else is well made though, and the Nirvana analogy is perfect.