Well it wouldn't be the first time.
I think the only way this debate could be settled is if there are clear parameters on what a Christmas movie is/isn't.
Example: Any movie you watch on Christmas as a tradition vs A movie with Christmas and/or Christmas themes and tones being
essential to the plot of the story line, etc. etc. That also begs the questions of what is required to be essential to a plot, but that's another stocking to fill.
Also, If you're going to go the "tradition" route that is obviously going to be very subjective and individualized. It was mentioned earlier by another member that in other countries they eat KFC on Christmas which makes it a Christmas food..for them. Which is fine. But if nothing about the fried chicken is related to Christmas other than timing (no seasonal ingredients or changes to reflect the nature of Christmas flavors, story, characters etc.) than the sentiment of it being a Christmas food only exists in the the minds of the people eating and not the food itself making it a Christmas tradition and not a Christmas food.