George One Time » That is what Moses did to the Midianites. Even all the baby boys were to be killed, not the female babies.
The difference is that both the Mideanites and the Canaanites were monsters. They weren't just peaceful farmers who suddenly found themselves facing Israelite swords and spears. The cultures were driven by base sexual rites that included the ritual murder of infants. The Canaanites were a profligate, bloodthirsty lot. They were beyond redemption. And though it's popular for critics to judge things with incomplete knowledge, I find it...unwise...to judge God based on incomplete knowledge.
When Korah appeared before Moses with his family and supporters because they couldn't hold the priesthood, and when Moses and Korah lit them to see to see whom God would support, there came a great earthquake and the ground opened and swallowed Korah, his family and his supporters. But even though Moses never touched Korah, it's interesting that the people blamed, not God, but Moses for their deaths. There's no human I know of who can create an eathquake, but the people apparently felt Moses had deceived God into backing him, and they were too frightened to blame God. Still, Moses defended the people.
To judge God or the Bible, one should know every aspect of the arguments one is purporting. God proposed wiping out all the people to settle Moses' problem, but He knew Moses would object, sparing them. So unless you know the nature of God and what the people were up to, you're in danger of judging wrongly. And many of the people died because they so presumed.