There are two schools of thought here. The first is that God really did command killing, and was perfectly justified, because the alternative would have been the annihilation of the only people prepared enough to bring about the saviour of the universe. The other interpretation is that the people in those times, limited in their understanding of God’s character, misattributed certain acts to God in their stories. The latter view is more reasonable, in my opinion.
But either way - it doesn’t change anything.
When you read the entire biblical story, one thing is abundantly clear: God’s providential plan was to save everyone and everything. He revealed himself, in the only way he could, to a particular tribe of people in history, and out of those people was born the saviour of the world.