What a wired take. I don't think Guy Fawkes, or Dia de Los Muertos aren't real holidays just because they aren't part of my cultural heritage.

The curmudgeon's point is that early celebration of one holiday shouldn't eclipse another. But based on the sentiment, license plate shape, and visible flag, I think we can assume the photo is of an American by an American. So Thanksgiving is a fair benchmark for the start of Advent for them.