I stopped believing in Santa Clause when I was 8 or 9. My mom always told us that when we stopped believing, Santa would stop bringing presents. We had no long-lasting psychological damage as far as I can tell. Dawkins may be intelligent, but he’s an idiot.
You are right. I was the oldest so in order to insist that I keep my big mouth shut my parents told us the same thing. My son 16 has 3 siblings and I want them to “believe” for as long as possible. It just makes it nicer in my opinion. We definitely focus on the Birth of Christ, but we also celebrate the spirit of Santa Claus who was a Christian himself. I think they both can work together.