Because of Santa's commercial aspect, most religions celebrate him for the kids. He is a symbol of the human spirit IMO. The holiday decorations will continue to be part of our spirit no matter the religion, they are just pretty.
Separation of church and state is mandatory and is clearly stated in the Constitution. Christian symbols continue to be displayed in this country's monuments and federal establishments. However, the values upon which those establishments were built were derived from the fundaments of Christianity. I view them not as a threat to that separation but as a historical display.
I am not a "churchy" person, I am more scientific, but I certainly believe that the values taught by that particular religion among others, are truths for a civilized conglomerated society. So I don't have a problem with any of those displays, or any display for that matter. I am not easily influenced by things of that nature so I don't feel it a threat to my belief system.
PS- Everybody wang-chung tonight.
