This answers my question, I suppose:

Christian has three primary objections. First, he doesn’t see Jesus anywhere but the nativity scene, crammed into the corner. Kirk answers him with a long refresher about how Christ was born to die on the cross and redeem man. Fine. Christian doesn’t like the Christmas tree, either. No Christmas trees in the Bible. But Kirk has an explanation for that, too: Man fell because Adam ate fruit from the wrong tree. Man was redeemed because Christ died on a wooden cross. ERGO, CHRISTMAS TREES: “When you walk into a Christmas tree lot, I want you to see hundreds of crosses that will never be used because of Jesus’s finished work.” Pretty sure that’s not the historical root of the tradition, but whatever.

Oh, and that business about the winter solstice? Kirk’s not persuaded:

“The early church had plenty of good reasons to celebrate the birth of Jesus on December 25, and it had nothing to do with the winter solstice. [Note: he does not outline these reasons.] By the way, last I checked? It was God who made the winter solstice when he set the planets on their path around the sun. And it’s actually quite fitting that we celebrate the birth of Jesus in the bleak midwinter, when the world appears to be sleeping and dying.”

Ah, the FIRE EVERYTHING school of theological argument.

jezebel.com