Because, in North America they are mostly Christian. Not the celebrations, but the people. Majority rules, man. It isn't fair, but life isn't fair. Same reason why in say, Saudi Arabia, you don't celebrate Christmas.
Or maybe you do. I never went there.
Wiccan symbols on graves? Well, the desecration of Christian cemeteries upsets me, too.
So everyone who isn't a Christian has less rights than you, I see. I'm glad you made your position so clear. The majority are white too, right.
The soldiers give there life so you can enjoy your freedom, but you have no problem trampling on theirs, big of you.