I don't understand your point. Why does mentioning that people historically hurt and killed other people make any case other than that harm caused is the sole basis for determining what we should be morally against? Why do you think historians deigned to record all those instances you mention? I think it's to help us figure out what not to do.
My point is that nature doesn't dictate anything when pitted against human intelligence. We submit to nature at will, and we ignore it at will.
We control it, not the other way round.
