I remember thinking that it was curious when Carl Sagan was deeply agnostic about God, yet so committed to searching for intelligent life in the universe. I thought I noticed then that people who were so curious about that were almost invariably not believers in the Christian God in any usual form. That just follows a prejudice of mine, that they would think that. I don't actually know it. I still think it true, but it would be easy to talk me out of it with a little good data.
Slate Star Codex (sidebar) has a lot of links and connections to the rationalist/humanist communities. I think I am seeing the same thing again over there. I will postulate, for contemplation, that there is some conservation of this belief in the human personality. We want to believe that there is something out there that can instruct us, guide us, improve us. When we give up YHWH, we find some less-threatening cycle of lives, or oneness with the universe, or distant wise ones to believe in instead. (I find all of these to be ultimately much more threatening, but they don't look it at first.)
I do not claim this is universal. I suspect there are people who have none of this belief at all, neither Abrahamic nor SETI. Yet the replacements have observably sprung up in the West in step with the reduction of monotheistic belief.