Anything which is permissible for a piloted bomber to destroy is surely okay for a drone to destroy as well, yes? Why the focus on drones per se?
Yes, civilian deaths are bad. Yes, war is bad. Yes, perhaps the wars in Afghanistan and Pakistan should be ended tomorrow. So why don't we discuss those?
Drones seem utterly irrelevant:
1. Do drones cause more civilian casualties than traditional air strikes? If anything it seems that they inflict fewer. Thus focussing on this aspect actually hurts their case.
2. Do drones terrorize civilians more than a traditional infantry occupation, such as that prosecuted by the US in Iraq? I honestly have no idea, but the answer doesn't seem obvious.
3. Do drones make the US less safe than a traditional infantry based occupation? Again, I've got no idea.
4. This point is silly. In war you needn't get clearance before killing one's enemies - attempting to do so constitutes an increase in respect for human life.