As an atheist, I wish I could file a friend of the court brief in favor of Christmas. I've always loved and celebrated Christmas.
It is a time to gather with family and friends. It is a time when we all seem to care for each other a little more than usual. It is a celebration of humankind, and for some parts of society, they bring their faith into that celebration because that is part of who they are.
I enjoy Santa, Christmas trees, and presents. However, it is no skin off my nose if others also include the nativity, or Christmas mass, or a Chanukiah as part of their celebration. It is all part of Christmas.