The model of God proffered by the given religions, just doesn't explain or predict what actually happens. If there was some omniscient, omnipotent deity with super powers of creation who loved mankind, then why does stuff like Las Vegas happen?
A better model would be some "Source" for the existence of the universe as we perceive it; a source with far greater knowledge and wisdom than mankind now possesses, that brought existence into existence, a perfected product, that was left to operate according to the laws and regulations established at the time of creation. Included in existence's possibilities is that sh!t happens.
That makes sense to me. It doesn't mean that this is actually the case.
As to atheists converting, what about people of devout faith moving to atheism or agnosticism? There's a bunch of those too. So what!?