Bitch PhD has an interesting article, “How I got to be an atheist”, which I think will ring a bell with many who found the faith within which they had been raised intolerant and inflexible, and just not up to the job of supporting a humane and loving sense of human morality.
The first moment when, in my teens, the Christian brother who taught me religion argued that God must be the source of all morality because if there was no God there would be no reason not to kill or steal, my eyes glazed over and I knew there had to be more to morality than such a nonsensical argument. We have an innate sense of fairness, and at the time as a teenager I naturally assumed that humans evolved that way. Finding Dawkins’ work on this (for instance Nice Guys Finish First in The Selfish Gene) was nice, but it only confirmed what was already obvious: the rules of the bible exist because humans have this sense of fairness and humans wrote the bible.
The savage barbarism of Deuteronomy itself shows how human standards have changed over the millennia, but also in Deuteronomy there is that same sense that fairness should apply. It is a very human code, full of faults that are visible to us because we no longer have the way of life that made the nonsensical rules and laws of that code make any kind of sense. We should not look to the hidebound and often quite barbaric religions for a moral code. We’re doing just fine without them.