I feel the flat earth might not be best reference. Because were not saying whether it's real or not were saying what the form is. I can add triangle earth square earth penis shaped earth U cant add to this argument. There r two sides u either believe all powerful being outside is real or u believe it's not real. If it's an all powerful being nothing can be greater and nothing smaller can compare to it. So its almost like light. There is light and there is dark they cant both be possible in same space. These two side r the same way God and no God can not both exist in same thought. So i guess In a way atheist isnt religion and isnt something u can claim its what happens when u remain outside any thought of the idea of God. So anyone that say I'm atheist they bring themselves to have the idea of God and no God in order to form there conclusion of no God. And that act is what makes God possible or u couldn't think about it to weight the idea and form ur coclusion