Atheism the default position?
You mention that the default position is atheistic, but that isn’t true. As a consequence of having social awareness humans are born with a default belief in supernatural powers (I read this in either a scientific american article or a times article). Most people begin by believing in religion and when they learn to question their beliefs they cast off their religion and become atheistic, but usually not the other way around.
I understand what you mean, but I still say that everyone begins as an atheist. Even if humans are born predisposed to believe in the supernatural, you are born with no knowledge of specific supernatural “facts”. A baby does not grow up to believe in God because it innately believes in God, but because it learned about God as part of learning culture, or concluded that God exists based on inadequate information. (And for those of you who say that one with adequate information can conclude that God exists, would you at least agree that a child is not intellectually rigorous enough to reach such a conclusion in a compelling way?)
But the human mind aside, atheism is the default position for science (just as disbelief in almost anything is the default position for science), and that is by far the more important point.