Ex:
Don't we already see this with drones? Meaning: video game weapons where we kill people from thousands of miles away (not just thousands of yards) and in most instances, we don't care what the "collateral damage" is. In fact, I believe the stated policy is: well, if these guys happened to be near a terrorist then obviously they're terrorists, too!
Same thing as people above noted with "smart bombs" starting with the original Iraq war footage. Boom! Fun!
Yet we are the same country that refuses to show graphic video of people on the receiving end of our munitions, innocent or otherwise. That way Americans can continue to watch the boom! while enjoying a plate of nachos and not see missing limbs, dead children or even what bullets actually do to humans.
So to answer your question: the more automated it gets, the worse it's going to get. Because it becomes impersonal.
I don't think many people would have a taste for killing if they had to stab somebody to death, which is why many use guns. Those who may not like even that option might be swayed by the idea that they're simply pointing something at somebody and pushing a button from a thousand yards/miles away. You don't have to be there to see the aftermath.