My answer is simple.
The Bible doesn’t tell us to celebrate Christmas nor does it forbid us to celebrate Christmas. It is in short a matter of personal freedom. Christians should feel free to put up a Christmas tree and give gifts if they like and churches should feel free to sing carols, have Christmas parties, and sponsor various Christmas outreach events.
But there is no command to do so.
Christmas is truly a Romans 14 issue. Some celebrate it, some don’t. Let those who celebrate not look down on those who don’t. Likewise let those who prefer not to celebrate Christmas look down on those who do.
By the way, to say this is not to endorse every single Christmas tradition. I’m simply saying that it is good to remember that Christ was born so that we might be saved. How we do it and when we do it is not commanded and is therefore a matter of Christian freedom.