Did you wade through that entire link?    Lot's of stuff in there.    Ultimately Christmas represents what we believe today.    I doubt Jesus was born on the 25th, but it seems a good time for Christians to celebrate a core event of their church.    I think those who do not believe in the mystical side of Christianity, may still embrace a lot of Christian morality without understanding it's roots.    Jesus (or as we would call him today "ThornyHead" or "EarDoctor") was fully human, by scriptural account

I'm friends with hundreds of Christians who have sat in church on Sundays, hearing the same recitations of scripture, yet coming to very different conclusion.   IMO the 'one way' believers are fooling themselves if they think they have a united Christian church that stands behind them.   

https://en.wikipedia.org/wiki/List_of_Christian_denominations

p.s. I love Christmas trees in all shapes and sizes.    I'm the kid on the stairs on Christmas morning.