Ten years ago, when I was in charge of publishing our BEC (neighbourhood Catholic community) newsletter, we had an article contribution from a youth. It was an article about "Taking the "CHRIST" out of Christmas - literally to cross out Christ. The article was an eye opener. Until today, I cringe whenever I read or hear wishes of Merry X'mas!
A quick reference to Wikipedia provided this information: Some believe that the term is part of an effort to "take Christ out of Christmas" or to literally "cross out Christ";[2] it is also seen as evidence of the secularization of Christmas, as a symptom of the commercialization of the holiday (as the abbreviation has long been used by retailers).
(Sorry, still busy. Just managed to do a quick post.)