The irony is that Santa -- the real Saint Nicholas -- was a minority whose people were later ethnically cleansed from Asia Minor to make way for the Turkish ethnostate. And now his secular caricature is being ethnically cleansed to make way for ... whatever.
Imagine Mel Gibson making a movie about the Esther story and releasing it around Purim, but in this version of the story Esther is all the worst stereotypes of a Jewish woman. And so a Catholic-coded white gentile man takes Esther's place in the harem because Ahasuerus's wives have always been Jewish women and it's time for a change. So the whole idea of the dutiful young women saving her people from genocide, the spirit of perseverance and survival, is lost. The characters are still there, Ahasuerus and Haman and some dude dressed up like Esther, but they aren't doing any of the things that give the story meaning, a meaning that is still celebrated today even by people who don't particularly care about the politics of the Persian Empire or believe that the story actually happened. Mel defends this by saying most Jews are only cultural Jews and therefore Purim has no religious significance, so loosen up, it's just a joke, man.
Even actual white supremacists would find that tasteless.