What makes you think these weapons will be discriminate? Who will be deploying them and against what will they deploy them? Drones are dual use technologies, the user matters. AI is also a dual use technology, the trainer matters. AI (poorly defined term almost always, but whatever) can be just as evil as a human, if not more so. It's hard enough to figure out what's a moral right vs. wrong as a human, I've yet to see a computer do that, and if it did, I'd argue it's just as easy to tell it to always choose wrong vs to always choose right.