My colleague from Canada was wearing this sweater at lunchtime in the office cafeteria this past Thursday. She said she bought it at the local department store nearby (in Germany).
I said: "Really? You got this sweater in Germany? A sweater with Merry Christmas written on it in English? This kitschy thing is being sold in Germany? She answered: "Oh yes, and the store had several different styles and colors related to Christmas".
Thus, the americanization and/or commercialization of holidays (and "fake" holidays like Halloween) in Germany continues. Regarding this topic you might also be interested in my blog Costume.