How long can the delay be between the fire button and they actual violent act? People shot un-recallable missiles and artillery that doesn't land for minutes but does sophisticated tracking and maneuvering in the meantime. Is that a drone?
Stop with the stupid nitpicking. You should already know the reason why we have humans in our war machines is that they are the ones with the authority to designate targets and deploy the weapon against the designated target.
It's not stupid nitpicking at all. If I designate Jon Doe as a target and have a swarm of drones do facial recognition the laws have to be clear enough to distinguish this from me putting a tracking device in Jon Doe's pocket and have a missile home in on that signal.
The counter-argument: it wouldn't be hard to design a system where a human remote-operator in Arizona is paid minimum wage to push a button whenever a screen in front of them turns red and says "FIRE".
Any regulation of lethal autonomous drones will require some nuance in the wording.
If the drone requires an operator to press the fire button, it is not fully autonomous. If it does not, it is.