I don't think that proving the non-existence of God was the point of her speech- she was, after all, speaking to a room full of atheists, so that'd be a bit of "preaching to the choir." :)

I think she was musing on the universal needs that people have and why some people turn to religion to fill those. I think she's wise to try to understand religion and religious people rather than just dismissing it and ridiculing people of faith as some atheists do.