My kids (USA public school - kindergarten) have learned about what Hanuukah celebrates, what Kwanzaa celebrates - and for Christmas all they are told about is how other cultures might celebrate it, but NOT what it's about! I think it's because if they did teach the Christian mythos alongside all the others, it might be allowing the children to think that Christianity might be a possibility instead of a defacto default state, and we couldn't have that, no, no!