It's always good to remind one's self and others the true meaning of this blessed holiday and why it fries the more panty-waist of one's brethren.
For example, these "squeaky wheels".
An answer to the militant atheist's crusade against the season:
The myths calling Christmas a myth:
Christians have also been accused of bastardising Saturnalia, another Roman holiday. This argument is flawed as well for several reasons. When the Romans celebrated Saturnalia, it was celebrated from December 17 through December 23. It was not one day. In fact, given the Roman calendar as being as it was, it would be hard to place a Christian holiday on any day in December with out being accused of appropriation. It would be hard to place Christmas on any day of the year with out facing similar accusations. Remember that the Romans had many holidays. Over 120 days of their year had a holiday on it. You could barely go more than 5 days with out celebrating something.
Why saying 'Merry Christmas' is important:
Back to the original dilemma: why say "Merry Christmas" as opposed to "Happy Holidays"? There is a problem in denying an event or holiday the specificity and uniqueness that it possesses. By lumping Christmas in with other holidays, you make Christmas generic, not special or with a purpose. "Holiday" could mean anything. Would it be amiss to say "Happy Holidays" for St. Valentine's Day? It is a holiday of sorts.
As it goes without saying, holidays aren't the same in every respect. Is Setsubun the same as Christmas? Is Hanukkah the same as Christmas? Obviously not. By not mentioning Christmas, you (to put it dramatically) rob it of its identity. Christmas has various rituals and memes all with significance. If Christmas was not omitted but diluted to something barely recognisable, that which made it special would fail to resonate with its observers. Any celebrations would be menial task for those accustomed to the holiday in its original form and a confusing, even belittling experience for those unused to such a holiday. Do we assume that by celebrating Christmas that those of other cultures cannot follow along? Do we trust them to be active in the celebrations if they so want? What must be going through a Hindu or Buddhist's mind when they are invited to a "winter holiday" party minus the Christmas tree and carols they've been apprised of in some fuzzy photograph in a magazine somewhere? Making assumptions on someone else's behalf is- well- offensive. Isn't it better to simply live or celebrate something than to hide it?