The Two Types of Atheists

Apparently my comments yesterday on the taxonomy of atheists weren't clear. A thoughtful reader writes:

If I'm understanding you, you believe there are just two types of people who don't believe in God -- ignoramuses and people like [Jerry] Coyne, who is "a peasant and a clod."

I ask, respectfully, if you can accept that there might be a third class of non-believer, someone who has fallen away after a sincere, intelligent examination of the evidence? I don't expect a reply and don't wish to...