"Gatling wrote that he created it to reduce the size of armies and so reduce the number of deaths by combat and disease, and to show how futile war is."
https://en.wikipedia.org/wiki/Gatling_gun
And yet, by making one person more powerful, I'm not sure that we've reduced the size of armies (certainly not in terms of support and logistics), but we have made it possible for one random person to do a lot of damage.
Theoretically, by only having robots fight each other, we could eliminate human warfare and human losses. Morality would be some kind of cold equation that could absolve people of guilt. In reality, this would just never happen. People are the source of conflict, and the source of killer robots.
I, for one, welcome the Butlerian Jihad.