There are good and bad things to having a PC culture. However, I do think respecting those of other religions, races, orientations, etc by watching what you say and do. I just don't understand people who thinks it's "cool" to not have a filter and then expect them to be fine with it.
I don't look at my wife in the morning (who is Japanese) and say "Holy hell, you look like Nagasaki this morning." That is incredibly insulting and rude obviously. However, I hear tons of Nagasaki/Hiroshima jokes that are supposed to be funny but they are just horrible.
When I meet someone for the first time, I am respectful and polite. I avoid trigger words and phrases that they might take offensively. Why ruin a portentially fruitful relationship just because of "free speech". I have tons of friends and acquaintances from are American, Japanese, Beitish, Chinese, Egyptian, Australian, Pakistani, Russian, Mexican, gay, lesbian, feminist, atheist, Christian, Muslim, Buddhist, etc etc. I learn to know what is acceptable around them And they know what's acceptable around me. But that's just me and my philosophy. It would be great if we could respect each other's beliefs but, obviously, some people can't keep thier thoughts to themselves.