So perhaps our treasured atheists can tell us exactly why they are atheists, rather than skeptics.

Because atheism is simply a shrug of the shoulders in the face of all the pro-God prosyletising. There is no need for sniffy scepticism. I told you why I'm an atheist less than week ago. I'm an atheist because:

There is no evidence for a God. The laws of nature can probably explain everything, though we do need to understand all those laws first. We are closing in on even the hardest issues still to be explained, and there's no need to interpose an "explanation" that explains nothing, least of all itself.

I can't see where I need to insert scepticism. It's really simple. I get with life as if God isn't there (except for arguing with believers who do stupid things like encourage their children to "believe in God" and force them to say prayers and go to religion lessons in silly faith schools, and with confounded idiots who preach creationist piffle in the face of all the evidence for evolution and who can't use the shift key). I'm not sceptical about what people want to believe. I was sceptical about ball lightning until I saw it for myself. The only thing I would say is that if you believe in God you should keep it strictly to yourself. If all believers did that right and moral thing, and left their kids alone, you wouldn't hear a peep from atheists.