Personally, I prefer the good old-fashioned "Merry Christmas" if that's your holiday. Why shouldn't you wish someone else well on that day (after all they probably benefit from getting the day off from work). I might wish someone I knew to be Jewish "Happy Holidays" or even "Happy Chanukkah". If, say, a Chinese friend wished me <Happy Chinese New Year whatever they say> I would not be offended in any way or say to them "Oh, you're so Chinese" I think we should have the right to wish others well in whatever way suits us without having to defend our point of view.
The OP says she took the comment as well meant and that is good. But I have heard and seen in print many comments (which I take to be criticisms) of Americanisms which, as an American, I find tedious at best. Sure, no one likes to think their language/country is being overrun by "foreign" expressions but does that mean the British should go back to speaking some ancient form of Celtic? Throughout history the language has taken on many foreign words and that makes the mix we have today.