Let me get one thing straight: I do not support this type of warfare (fire forget find). However, comparing to minefields there is one big difference; minefields though being static and dumb are very very dangerous for a very long time. Even today the minefields from Vietnam war keep getting toll amongst people that weren't even born when the mines were spread. Actually, it may well be that a child losing limb today for a land mine is the grand child of someone who weren't born when the war ended.
The drone, once out of battery/fuel will be harmless, depending on the weapons load of course.
I really want to emphasize that AI hunting down people without any chain of command with real human is not a good thing. But it is way different from mines.