This is exactly like ice skating
And about just as useful. Come on, does anyone think that killer robots are going to be programmed to avoid killing humans ? We can go on and on about how to make war a more pleasant experience, but the stark reality is that war is hell and, if you're in one, the only way to win is to kill the enemy before they kill you.
If you can't handle that truth, then don't start a war !
As for these namby-pamby rules, don't make me laugh. In a world as competitive as the weapons industry, where the norm is defined by what makes the most mayhem the most efficiently, the first company to market killer 'bots that DO target humans as well is going to reap the rewards, and the others will be reduced to vying for a spot in the United Nations pseudo Security Force.
Enough to make a 'bot worthy of the name want to fry its own circuits.