I know very intelligent anthropologists who are such atheistic Christians.But that is not analogous. An analogous story would be of somebody claiming to be a Christian, and then telling me that they rejected Christ as savior.
Even then, I wouldn't tell them that they aren't culturally Christian. There are large numbers of such people, they need to be acknowledged, and they need a name. They are exactly analogous to atheistic Jews - people who embrace the culture and social bonds of of Judaism, but not the theology. Such cultural Christians are commonplace. They're the people who check "Christian" on a survey, and celebrate Christmas and Easter - perhaps even in a church - but have no supernatural beliefs, and don't pray or read the bible.
@ Skombolis: this is what Topix is for: the civil and democratic exchange of ideas, not your ridiculous and abusive type of posting.
One recognizes the cultural significance and historical value Christianity has, and enjoys the powerful networking abilities of her church - it brings in speakers like Bishop Tutu and sponsors discussions on morality and so on. Yet she considers the stories in the Bible mythological fabrications.
Another believes that people require ritual through social interaction, so she holds a high place in her church. I don't know that she's atheist, but there's not a chance that she believes in Christian myths. Her husband and son openly make fun of Christianity, so I'm guessing it simply has some ritualistic significance to her.