I think what needs to be kept in mind that PC has a time and a place and as long as you know your audience you should be able to put words that fit the audience. Transmits your message with firmness without offending anyone who joins.
Basically, this time and age and the topics discussed in open forums like these, require not so much the writer to be careful (respect is never out of the question) but the reader to be even more careful. Had certain conversations happened behind closed doors or in close groups, no one would have feel ofended. In other words, people have not really changed and become more sensitive. We have become more open about our thoughts and belief.
The issue arises when someone enters discussion that is, by nature, controversial to their own beliefs and the feel that just because it is open, they can go in and trash the discussion. They feel they can go in there and demand sensibility towards themselves or attempt to tell others they are idiots because they don't share the same view. The solution in my view is simple. Stay out of topics you don't agree with and ask that people stay out of yours if they don't agree with you.