How secular is Christmas really?

Let me start by saying that I'm not against Christmas. This is just a thought that popped into my head over the holidays.

I've heard many atheists say that Christmas is a secular holiday. It's about giving gifts and spending time with family and friends. Jesus hardly comes up if at all. It's just a time meant for celebrating the company of those around you.

However, this is not entirely what Christmas is for young children who actually believe that Santa is a real person. These children will often watch movies and hear stories about Santa Clause where the main message is belief without evidence.

For example, in the movie Elf, Santa's sleigh won't fly because there isn't enough Christmas spirit. When it is suggested that he just reveal himself so that people will believe, he says "Christmas is about believing, not seeing." This is the cornerstone of religion. That belief for the sake of belief is a virtue.

For the majority of people, Christmas is a secular holiday. However, the lesson that these stories teach to children is very religious in its nature.