Well, firstly, He's not telling me to do anything like the things we're discussing, and there are no New Covenant Writings that speak of such things for us to be involved in, so no issue there. You're hard-pressed to associate me or anyone today with what you're attempting to do.
Secondly, you put yourself in the position of determining what is right & just in all times of history, knowing nothing but what you think you know now. You're simply not qualified, nor am I. You're the judge of no one but yourself, for yourself.
Thirdly, the punishment fits the crime. So, although we haven't discussed it, and although I understand many of the issues, I believe in capital punishment for certain crimes and I believe war can sadly be necessary.
Fourth, although genocide, including infanticide is indeed very tough to understand and relate to, once again, you know nothing about the circumstances, you have no ability to see forward through time (nor objectively backward it seems) to know what will take place, you nor anyone else has the ability to ascertain what is truly in the blood and soul of any people group, nor explain why some even from good families, simply become mass murders who may even enjoy eating their victims, so, again, you are not a qualified judge nor a meaningful critic. The instruction about God is that He does know such things and all of the facts by which to judge.
Next, you have no understanding of how law works and what can be instituted with success in a culture in times and among a generation where things are considered "normal." If you were to research the slavery issue and timing of God's Law you'd find it quite different in many ways to the slavery you're familiar with and inserting into the issue apart from knowledge. Your biased view is nothing for me to get into with you. There are plenty of researched writings on the topic if you're truly interested and can even remotely find a position of impartiality from which to judge fairly. I doubt you could clear your hostility.
The bottom line in all of this is you're an atheist who has found a pet area for reasoning your rejection of God. Nothing new under the sun as has been said. You're clear on what can be expected from you - God's bad - you know better...