"why would you even think that a fictionalized account of how the Hebrews arrived at the same rules means that Jesus or Moses were frauds or fantasies?"
Because both claimed they were direct revelations from the God, not myths or legends. But I'm intrigued by your "*Aside from the first couple of commandments, the rest are simply common sense measures to allow people to live together peacefully."
Why, if there is noone to ultimately answer to, should anyone worry about "living peacefully" with neighbors? That is a principle for the weak to live by, not the strong and clever. If I have the most powerful navy, why not impose "gunboat" diplomacy on lesser nations? If I have the most powerful army, why not impose my will on weaker peoples? If I'm stronger than my neighbor why not take his wife, car, house and money? The existentialist Jean-Paul Sartre says that "If God is dead, everything is permitted." In other words, if there is no supreme being to lay down the moral law, each individual is free to do as he or she pleases. Without a divine lawgiver, there can be no universal moral law.
If we are just random "accidents", products of chemicals, why should we care about anything but ourselves and why should we speculate about origins, purpose or being?
If in conquering everybody and taking their stuff, one manages somehow to avoid early retirement due to a dirk in the ribs, one may reflect in old age on whether working cooperatively in a community might not be less arduous and far more productive of happiness.
I thought that was Ivan in Dostoevsky's The Brothers Karamazov? (But then maybe this naive formulation isn't as persuasive coming from a fictional character that turns around and kills himself.)
Why did the Hebrews need to be told these things by God, but other societies were able to work it out for themselves?
You see, we have numerous data points of other societies coming up with similar codes; why should we accept Divine intervention for the Hebrew version? Simply because a book says that's the way it was?
Would that you were to examine your personal beliefs as thoroughly as you claim to examine scientific findings.
Societies based on such principals don't work. They are out-competed very effectively by societies that promote co-operation. Easy when you think about it, and mathematically demonstrable. Try googling the "repeated prisoner's dilemma" to see why benefits accrue from *not* picking the option with the biggest payoff all the time, if that option involves screwing your neighbour. Oddly enough the creationist's arch-demon Dawkins has done a lot of work in this area in his guise as a real biologist, rather than a pop-biologist.
Well, if Sartre said it, then I suppose Hell is other people too. Having lived in apartments before, I can at least confirm that Hell is noisy neighbors.