At least in America they have Thanksgiving, and a large enough jewish population celebrating Hanukkah(*), that "The Holiday season" actually makes some sense. Though I get the feeling it means people have trouble getting their head around any religions having major holidays outside that period or none within it.

That said: I'm not christian, and still sometimes send christmas cards :)

(*)Although apparently this isn't actually that big of a festival compared to some of the others at different times of year