How Darwin caused atheism

I agree, ToE has helped people become Atheists. It's not particularly unique in that. Science, in general, has helped people become Atheists because it has whittled away at the body of things people can point to and say "God did this". It has also promoted a healthy scepticism of absurd claims - have a read through the lists of Catholic saints and have a giggle at the miracles they "performed" to get sainted. It's a giggle. And, finally, it's offered a far better way to understand the world than a bunch of stuff some people made up.

I think it's a mistake to lump Mysticism and Atheism even though technically correct by a literalist derivation of the term Atheist.

Sure.There were Atheists before Darwin. Long, long before. But I don't think that's really the question posed - did Darwin, by discovering evolution, increase the number of Atheists? In my view, yes, he did. He's not alone in that, all historical science challenges mythical notions of creation; and all current science challenges the need for the supernatural. But Darwin, in explaining humanity, struck a blow to the heart of the need for religion.

Well, Darwin wasn't (publicly) an atheist - although he stopped going to church - contributed nothing to atheist philosophy, and didn't advocate for atheism so it's not clear what place he would have in such an article.