> why is it so hard to not be a jerk to other people? That's really the essence of "being PC". Treat others with respect.
Other replies have already hit the main points of why this position doesn't really make sense. Mostly it comes down to "jerk" being a subjective term.
However, I'd take thing a step further even. Why is it a problem if someone is a jerk? As adults shouldn't we be trivially able to disregard the aspects of someones communication we deem "jerky"? Why do we consider it reasonable to escalate hostility when someone is being (what we perceive as) a jerk? "Sticks and stones my break my bones, but words will never hurt me", is an objectively true statement. Any harm done by words is self inflicted. If we use the basic, nearly automatic, capacity we have to filter communication, "jerks" aren't really a problem.