Abortion advocates (both life and choice) are the worst. Like many atheists and vegans, all they can think and talk about is that one thing they're obsessed with. The tasteless display of his political beliefs isn't even the worst part about this. It's his singing. People with a personality of a pencil eraser shouldn't try to entertain.
But yeah, he's using Christmas as an opportunity to spew his views on a polarizing topic. He's gotta be fun around the ol' Christmas tree.