That's no indicator that Atheism is the default position. Children certainly would believe in something like that, and they also believe in Santa and the Easter Bunny. This is an indicator that humans have an inherent idea of a higher power.
so, is believing in Shnorklekus the default then? If you say no, then you're agreeing that atheism is the default. If you say yes, then please explain how you came to that conclusion.