I gave up trying to be PC quite a while ago. No matter how hard you try, you are going to offend someone. I still say "Merry Christmas" to anyone. If the someone to whom I am saying is offended by this, they are more than free to correct me and their complaint will be registered and corrected. But not if they overreact and go off on me or something of the like. If people are calm and civil towards me, I shall try to treat them with the same respect.
P.S. Merry Christma-Chaunu-Cuanza-ka