Sorry, I missed that.
Her reasons were simple, in her mind.
Short version of the lecture: She says that her family celebrates Christmas, and it isn't in their tradition to acknowledge any other holidays, and when people say "Happy Holidays", it only perpetuates the "intermixing" of holidays that have nothing to do with Christmas, which is what this time of year is for. For her and her family, and "America".
Again, while I didn't agree with any of the logic, and found flaws in it, I know well enough to know that it wasn't the time or place to jump on a soapbox.
I usually just say whatever comes to mind. I mean, I don't celebrate Christmas (at least not within family, with friends, I suppose I'm halfway in...nothing sexual.) but if someone says "Merry Christmas" to me, it's not like I'm all, "HEY! you take that bullshit back right this second!"