Political Correctness

The previous post urged me to write about something that I've been thinking about for some time now.This quote from John Cloud's article I posted from Time magazine, I really like :

"Speech codes are one of the many social devices that keep us from all murdering each other with our bare hands in the grocery aisle."

That is a very true statement. So this makes me ask: How much of a person's "personal identity" is defined by religion? The only way I can explain why people get upset when someone questions their belief (or lack there of) is that they take it personally at some level. So does that mean our personal identities have a "religious", "spiritual", "non-religious" component, depending on what we choose to believe? Is religion a part of our identity (or made a part of our identity) as much as our skin color, body shape, and sexual orientation? Do we have to be politically correct when it comes to religious beliefs/subjects and matters of faith? I think as long as it's a two-way street, there's no harm in that. Does that go against reason when you have to tolerate dogmatic nonsense? Possibly so...But it is maybe better than "murdering each other with our bare hands". What do you think?