Here's the normblog contribution to the following idea: it's perfectly OK to wish people a Merry Christmas in countries in which large numbers of them celebrate Christmas and/or when those towards whom the salutation is directed are likely to be pleased rather than offended by it.
The normblog contribution is this sling Santa across the ravine game. (Click on the image of Santa's catapult to get it moving, and then click-and-drag the catapult back, though not too far, to hurl him across the ravine.)
Mutatis mutandis (or here, for lawyers) with respect to Chanukah, Diwali, Eid, etc. (Thanks: the KP.)
Postscript: 343.9 for anyone who's interested.