Oh yes you are right, I hate that one too.
I found a funny article that was trying to decide which was worse: So This Is Christmas or Wonderful Christmastime. There was a lot of hate for both. I think it was wrong to conclude McCartney’s was worse. Musically it may have been worse, but for missing the spirit of Christmas Lennon wins. Not that Wonderful Christmastime was spiritual; it just wasn’t as smarmily secular as Lennon’s.