Everybody likes Christmas songs and this is a very pretty version of this old song. I'm not asking you to suspend your disbelief, as Mary's mother and Joseph must have done on that 'immaculate conception' shit Mary thought up to cover her ass, which story you wouldn't have tried on your mother and fiancé in your wildest dreams, but which for better or worse has lasted longer than if she said she caught it from a toilet seat, so just take it for what it's worth. Jesus was just a baby, after all. He didn't cause any lasting trouble until long after he was dead and that wasn't really his fault anyway.
We'll get to the PR stunt the world's been paying for for two thousand years come Easter.