In The Washington Post, E. J. Dionne Jr. wrote a couple of years ago:
It shouldn't be hard to acknowledge that there is prejudice in some sectors of our society against those who hold traditionalist, evangelical or fundamentalist religious views. ... But such respect cannot come at the expense of the rights of those who are not Christian. At the personal level: What in the world is "Christian" about insisting on saying "Merry Christmas" to a devout Jew or Hindu who might reasonably view the statement as a sign of disrespect? At the level of government: Is it really "Christian" for a religious majority to press its advantage over religious minorities, including nonbelievers?
The great Protestant theologian Reinhold Niebuhr wrote that "the chief source of man's inhumanity to man seems to be the tribal limits of his sense of obligation to other men." I fear that in these Christmas debates, Christians are behaving not as Christians but as a tribe: "We will pound them if they get in the way of our customs and rituals." Tribal behavior is antithetical to the spirit of peace and good will. In this season, we ought to be taking the most expansive possible view of our obligations to others.
I think that Dionne is really on to something here when he identifies people's reactions as being more tribal than religious (with religion serving as the basis for tribal identity). Some Christians are turning the phrase "Merry Christmas" into a fetish, something that is done for its own sake instead of using it as a greeting that means something more. In the long run, such a tactic is more likely to backfire than to accomplish anything substantive.