Putting the Chi back into Xmas

I am delighted to see Ed Cook in Ralph the Sacred River, homing in on something that has always annoyed me, perhaps because I too was taught the proper derivation at my mother's knee, that "Xmas" is not a sacreligious attempt to write Christ out of Christmas (I've heard entire sermons based on this premise). One might as well tut-tut at the Chi-Rho in the catacombs.