Comment 11 by Eosimias :

The way atheism is used in the works of Dawkins, Harris, etc. and what most people on this site and elsewhere mean by it is not just a neutral lack of belief in any God but an affirmative belief that there is no God.

That's simply not true. Most atheists recognize weak/negative atheism vs strong/positive atheism. Someone who does not believe in a god can not be a theist and is therefore not (AKA "a") theistic.

Even Dawkins puts himself at a 6 (out of 7) on the positive atheism scale.

I don't know what scale you are referencing. But chapter four of The God Delusion is titled "Why There Almost Certainly Is No God". Keeping in mind that Dawkins is a scientist and hence would also say things like "why evolution/relativity are almost certainly true" that seems pretty strong/positive/affirmative to me.