Christmas derives from Saturnalia festival at roman empire. Now there was a lot of after harvest festivals at the start of the winter in numerous cultures, but the one romans had was the biggest and most influental. It's easy to realise once you have in mind that Roman empire was wast in land and most advanced civilization durning those years in entire world.
Now then new religion comes into place they ussaly try to overcome the festivals and celebrations which people once already had and claim them as their own.
Knowing that christams wasn't about religinion in the first place, I don't see why people shouldn't ceberate this time of the year in the future.
For lols: Bible forbids people to bring up tree in a house and decorate it. Becouse that's and Idol. And Abraham's god hates Idols. ;D campaigns like "bring back jesus to x-mas" are stupid from the core. Cuz Jesus or any religuos stuff doesn't belong there from very start.