If one distinguishes between atheism and agnosticism (many don't, but that makes it impossible to have a coherent conversation with them on the subject), atheism is the affirmative belief there is no deity (where agnosticism is more "we don't know, "we can't know" or "I don't care").
Since proof that the deity of any major religion exists, or doesn't exist, is, by definition, impossible, that affirmative belief there is not God is exactly as much an act of faith as the belief there is.
And any faith can be proselytized for. And yes, Dawkins does. He's always been a bit of a nutbar, and more than a little bit of an asshole.
(I'll be modded down for saying that first part out loud, but that's inevitable when someone challenges a person's faith. Especially from someone who is in deep deniable that it is, in fact, faith.)