Well, is it?
I mean, if DIE HARD now widely considered an Xmas film because it takes places during, and constantly references, the holidays, then I say, yes, BATMAN RETURNS is indeed a Christmas movie.
Of course, the real litmus test for any Xmas flick is this: do you always make a point to watch it during the holidays?
BATMAN RETURNS fails that test for me. At least for now.
What about you? Is BR an Xmas flick to you? And if so, does it pass that litmus test?