I don't wanna be the party pooper here, but Die Hard is a specifically American Christmas Movie. I'm not saying that other people can't or shouldn't enjoy it as a Christmas Movie if so inclined.
But as a German what we "traditionally" watch as Christmas Movies/Shows is something completely different (though also varying greatly from region to region and family to family. I for one still enjoy "Weihnachten bei den Hoppenstedts" a lot my father mostly insists on seeing "Familie Heinz Becker feiert Weihnachten". A movie a lot of people consider to be a Christmas Movie as far as I can tell is "Drei Haselnüsse für Aschenbrödel".
Again I'm not saying that people can't consider "American" Christmas Movies as their own or make them their traditions a friend of mine insists that "In Bruges" is the ultimate Christmas Movie. I just think saying "We all agree" is making it to simple
Edit: Read some more comments and maybe I misunderstood the premise. I'm not saying "Die Hard is not a Christmas Movie" what I'm trying to say is "Christmas Movies are what people make their Christmas Movie regardless of if they are Christmas-y" if I started watching Shrek at every Christmas it would be my Christmas Movie. But I feel what OP wanted to say was "There are Movies that are considered Christmas Movies because of the content and Die Hard should be considered one of them".