Yes, I'm a heathen. Yes, I disagree with a lot of what the church has done in the name of its God and Christ.
But I still like Christmas as a celebration of family and love.
It doesn't bother me if someone wishes me a Merry Christmas. It's meant to be a happy sentiment of peace, and joy, and love. I can take it as that, no matter if they're super fundamental Christian, or totally atheist, or whatnot.
So, Merry Christmas to you and yours.