My initial sense is it's not a Christmas movie because the typical example of such is a movie that has something like "the joy of Christmas" as its core message or theme. But I'm hardly the most buff of film buffs, so I wonder: are the any movies with something of a negative message, or just any counterexample that is clearly a Christmas movie that doesn't meet this criteria of "joy" etc.?
"Bad Santa" is absolutely, unironically, my favorite Christmas movie of all time. And while Billy Bob Thorton's character does have a measure of redemption at the end, it overall is a dark comedy that is clearly the opposite of what you describe.
