I’m not normally in the habit of giving advice to Christians about how to observe their faith. But as a tactical matter, if you want to put the Christ back in Christmas, my advice would be to follow Jesus’s exhortation to turn the other cheek. The best offense against humorless prigs isn’t counterveiling humorless priggery. It’s good cheer. If someone gets angry when you say, “Merry Christmas!” chuckle and tell them, “For your sake, I won’t tell Santa about this.”
And take comfort in the knowledge that the Christmas haters are not merely losers, they are losing. Most Americans — who spend almost a trillion dollars a year at Christmastime by the way — understand those people are idiots. If anything, Christmas keeps winning in the war on Christmas because Christmas is so much Odin-damn fun! So enjoy the holiday on Dickensian grounds — faith, family, fun all mixed into one. Say “Merry Christmas” with joy in your heart and have a good time — if for no other reason than the fact that nothing pisses off the people who hate Christmas more than people actually enjoying Christmas.