Although not completely related, may I look at it a step further. I'll try to explain. Most definitely there is an ethical issue, no doubt at all! But the question is, will it always be possible to have "a man in the loop"? Situation: a navy ship at sea being attacked by multiple rockets coming in at Mach 5 speed at very low level above the sea. How much time is there to make decisions? Mili-seconds? There is an excellent, private Dutch site about navy ships (Marineschepen.nl) where exactly this issue was raised recently in an article about radar systems. The site is in Dutch. https://marineschepen.nl/nieuws/Thales-AWWS-radar-voor-nieuwe-fregatten-080319.html
Even now, with IFF systems, friends sometimes get hit. Systems basically say "Hey, I have this target ready to hit. Shall I hit it?". So when there's a lot happening, sometimes humans just say "Whatever, sure".
"A robot dog pulled a 3-ton plane, and we're not scared at all... The HyQReal pulled a three-ton Piaggio P180 Avanti passenger airplane almost 33 feet last week at the Genova Airport in Italy,..." https://www.cnet.com/news/a-robot-dog-just-pulled-a-3-ton-plane-and-were-not-scared-at-all/
