Skynet? Really? That's the one thing /.-readers can think of that could go wrong with this technology?
So, as long as we don't develop self-aware AI that somehow decides to rise against its creator, we're fine with having weaponry that can acquire and engage human targets autonomously? We're fine with armies of these devices at the direction of a few mad men, with just a single conscience deciding the fate of thousands instead of having a human at every trigger?
We should oppose this type of weapon for the same reason we feel it's well beyond humane to use nukes, chemical weapons or even cluster munition. Because these weapons kill indiscriminately and wholesale, at the direction of perpetrators of crimes against humanity.
And don't start about the military command structure and how everything is ultimately always at the command of the commander in chief, because all evidence shows that the weak point always lies with the soldier that has to pull the trigger and decide to kill a fellow human being. And personally, I like it fine that way.