I might have phrased it a little vaguely in my post - sorry, it was late and I am in a lot of pain right now - but I did address this in my post. The argument was not between sufficient reasons against God existing and sufficient reasons for God lacking.
As I said: "...sufficient reasons to reject the existence of God, topping sufficient reasons to believe in God."
Meaning: there are both sufficient reasons for and against God, and the person, for whatever reasons, prefers the against side. Such a person would not think there are no sufficient reasons for God, and still be an atheist.