The many nonbelievers [Zuckerman] interviewed, both informally and in structured, taped and transcribed sessions, were anything but antireligious, for example. They typically balked at the label "atheist.” An overwhelming majority had in fact been baptized, and many had been confirmed or married in church.Zuckerman wrote from Scandinavia, but I've seen the same attitudes in the USA. I had lunch with with a guy a few years back. By my lights, he was completely atheist. Didn't believe in the God in Heaven, didn't believe in God as the ground of being or God as infinite love. A "Physics is All There Is" bumper-sticker kind of guy. Except that he was chair of the Evangelism Committee of one of neighboring mainline churches. He didn't strike me as a hypocrite; he felt little contradiction between his private views and his office.
For me, if I'm a member of a church, it is very important that the doctrine I hear espoused from the pulpit be consonant with what I believe. So I'm a UU. But some other people ... well, I wish I understood better what these folk mean when they say they're Christians and not atheists.