First, there are two kinds of atheism: active and passive atheism. Active atheism is a religion. It is an active belief, even a need, that there MUST BE NO GOD.
Passive atheism again is of two kinds. The first is actually a form of self-worship, and is the most common; in the end, such a passive atheist ends up enslaved to many things. The second, I think to be extremely rare, but is more of an unawareness of God.
That last kind of atheism, yes, is not a religion.
As far as it goes, it takes actual believing effort to ignore or deny the gaps. Moreover, when I talk of gaps, they are different for you and for me, because I have no gap for (for example) the Bible, Noah's flood, and asteroids. You may have no gap for asteroids, but have a gap for Noah's flood. BOTH of us have gaps for the severity of the asteroid problem: is the Holocene Working Group more right, or is the traditional interpretation of asteroid frequency more right? We discuss and read and argue, but currently we don't know.
The gaps don't terrify either the Christian or the atheist, surely. To say otherwise is to be hot-winded. But the gaps are evidence that one's current working theory might be wrong. And my point was that to be SURE in your atheistic faith (for an ironic association of terms), you have to deny the gaps.
I acknowledge the gaps. Maybe that is why I can be a Christian, and yet sometimes be on the edge of despair. But that isn't all of it. Some of it has to do with the future I see. Some of it has to do with the people around me. A lot of it may have to do with my own biochemical and genetic makeup. As I wrote before, I'm not quite 100% sure what the source is. It may not matter.