Just because the origin of a celebration may be mythic or legendary, I don't see why I should try and write it out of social history, or my present culture. There's good bits in the Christ story, and it's a great excuse for some mass family gatherings, and general giving and goodwill. As long as you don't tell me I'm going to hell, I'm not going to start pulling out archaeological and historical evidence on you. Let's smile at each other, wish each other well, and have a good time.