Are you going to criticize people for painting eggs and hiding them for their kids when they don't believe in Jesus? Even thought it's associated with the celebration of Jesus' resurrection its actual connection to Christianity is tenuous at best. People adapt popular customs and impart the meaning to it they choose. If people want to have a tree and lights and exchange gifts and spend time with family, Christmas is a great opportunity to do it.
And unlike the JWs, we are not afraid of other religions. I respect the rights of people to believe and practice their religion however they choose as long as it doesn't hurt others (shunning, anyone?). And if someone I care about engages in religious activities, I'll participate to an extent to show my support even though I don't believe in it. I'm neither Christian nor Jewish but I'm giving a dreidel to a friend of mine for Christmas. He's pagan. But he wants a dreidel for Christmas.
You remind me of the people who say "My god is your god, even if you don't believe it." No. You may believe that your god created me but that doesn't make him my god. He wouldn't be my god unless I chose to worship him.
I enjoy the story of the Christ in the same way that I enjoy stories of the Greek/Roman deities. I don't have to believe it's true to have fun with it. Without having done much research on the subject (yet) I do believe in the existence of Jesus, just not his divinity. I respect and agree with many of his teachings. Not believing in God does not preclude celebrating the man.