If someone is deeply troubled and leaves the faith because of what I just said, then I think its because they weren't aware of what the Books of Genesis up to Joshua actually talked about. More then likely they probably belong to a church that or group that prefers to overlook the old testament. Mainly because the Old Testament is a testament to the Barbaric nature of human society up and through the Roman Empire. Its bloody, speaking of wars, the genocide of many tribes, the testing of people's faith through massive acts of destruction and misery. Its history man, its not just Jewish history either. Early Human civilization was brutal and frought with behavior that we would find horrid today. Such as rape, genocide, slavery, lack of human rights, and death penalties/ exile for things we now consider petty crime. Its not a stumbling block man, its just how things used to work.
The other lesson is that if you didn't worship Yahweh, you were destined to be destroyed by the nation of Isreal and not even the women and children would be spared. Your city would be burned to the ground and all your inhabitants will be killed or taken as slaves ( and not the let go after a few years thing, no its slaves for life deal and you would do work until you couldn't work anymore and it would be demeaning.) Those interested should read the book of Joshua. ;)