What if I want to be inclusive of people who have no desire to avoid vulgarity? What if I want my workplace to have a bawdy culture? What concern is that of people who don't so desire? Not every space should exist within the parameters of the lowest common comfort level; no one belongs(that is, finds comfort and solace in the culture and circumstances of) everywhere, and that is okay.
P.C. is not basic respect, it is the deliberate replacement of authentic human interaction with bland milquetoast inoffensiveness.
What concern is it to other people if you want to be a rude jerk? Quite a bit, actually. It comes down to manners and the social contract that keeps society from devolving.
Manners, common ettiquette, politeness, all those things your momma (ought to have) taught you are constraints upon "authentic human interaction". Even animals have a concept of proper social etiquette.
That's what PC is. It's simply about not being an *******. If you want to go around calling people the N-word, that's your perogative, and it's mine to call you an ******* for it. Are you seriously arguing that you need a "safe space" where you can use racial slurs and misogynistic jokes without being called a jerk for it?
Now, I have a feeling you think "manners" are all the nice social constraints you agree with, and PC are all those social constraints you disagree with. But tell me, what's the difference between being polite and being PC"? Are they both not constraints upon your "authentic" human interactions?