Christmas has only recently been considered a Christian holiday. Look to many history books, and you can find information similar to this:
The Puritans considered Christmas un-Christian, and hoped to keep it out of America. They could not find Dec. 25 in the Bible, their sole source of religious guidance, and insisted that the date derived from Saturnalia, the Roman heathens' wintertime celebration. On their first Dec. 25 in the New World, in 1620, the Puritans worked on building projects and ostentatiously ignored the holiday. From 1659 to 1681 Massachusetts went further, making celebrating Christmas "by forbearing of labor, feasting or in any other way" a crime.
The concern that Christmas distracted from religious piety continued even after Puritanism waned. In 1827, an Episcopal bishop lamented that the Devil had stolen Christmas "and converted it into a day of worldly festivity, shooting and swearing." Throughout the 1800's, many religious leaders were still trying to hold the line. As late as 1855, New York newspapers reported that Presbyterian, Baptist and Methodist churches were closed on Dec. 25 because "they do not accept the day as a Holy One." On the eve of the Civil War, Christmas was recognized in just 18 states.
Now, under the guise of putting the Christ back in Christmas, some are calling for a boycott of stores that wish you a "Happy Holiday," rather than a "Merry Christmas." What's ironic is that this stance actually seeks to make Christmas more commercial by connecting the word "Christmas" more solidly with the consumerist orgy Christmas was originally created to be.
Christmas gained popularity when it was transformed into a domestic celebration, after the publication of Clement Clarke Moore's "Visit from St. Nicholas" and Thomas Nast's Harper's Weekly drawings, which created the image of a white-bearded Santa who gave gifts to children. The new emphasis lessened religious leaders' worries that the holiday would be given over to drinking and swearing, but it introduced another concern: commercialism. By the 1920's, the retail industry had adopted Christmas as its own, sponsoring annual ceremonies to kick off the "Christmas shopping season."
The best idea I have ever read about returning sanity to Christmas was Hundred Dollar Holiday by Bill McKibben. He discusses the history of Christmas, and he laments how Christmas becomes so busy, depressing and expensive. His solution is elegant, and I would love to try it, but it would be hard for most people to convince their entire families to test his solution.
This year, my wife's family has decided to forgo buying each other gifts, instead opting to purchase gifts for children at Vanessa Behan Crisis Nursery. In my opinion, this is a great way to make the holiday more meaningful. While this solution is still "commercial," it makes Christmas about giving rather than getting.
The above quotes came from this article.