As quite a few commentators have pointed out, one of the chief problems with current American foreign policy is less about the utilization of drones than America's penchant for killing indiscriminately. Drones are but one means of accomplishing this. And yet, the drone program has served as the fulcrum of criticism. I think this is the case because drones represent a cowardly way of doing the dirty deed.
Drones operate much the same way as long-range missiles. It allows a nation to rain down terror on others, while not exposing your own troops or civilian population to much danger. Drones take this a step further because the other side often doesn't have the faintest idea where the computer operators are housed. They could be almost anywhere.
In the old days, if you wanted to punish or attack others aggressively, you had to be in close proximity. By being so near by, your troops were exposed to the real possibility of retaliation. While the other side might experience the greatest number of casualties, your side took its lumps as well. So, attacks of this nature were based on cold calculations: How many casualties on our side can we accept in order to brutalize the other?
Drones have obliterated this calculation. Now you can brutalize the other side without worrying much at all about near-term reprisals. You can kill and maim others willy-nilly and, once a mission is completed, the attackers get to go home to drink martinis and lounge in the sun. In a manner of speaking, it is like shooting fish in a barrel or those hunters who go to wildlife parks to shoot drugged animals contained by fences.