The country of USA has been diplomatic in ensuring peace and in the removal of harmful violent non state actors (terrorists) by the means of drones with prior permission from the respective state governments.Although there has been some unwanted causalities, steps have been ensured so as to minimize the repercussions for the greater good
If one is to answer this question, they should ask themselves: "Why UAVs and not manned jets"? The answer to that is because manned jets cost more, and there is risk human life on the part of the pilot (and co-pilot if applicable). Drones are unmanned, so there is no worry of loss of life, they work on the same RoE that everyone else in the military branch does, and they are a lot cheaper ($4.3 million for a predator, vs $150 million for an F-22).
Drone Attacks kill innocent men, women and children . No one has the right to simply go and kill anyone they wish without any repercussions . These attacks lead to even more hatred and terrorism. Ethically speaking if you kill women and children and call them causalities of war then you are no better than the very people you are fighting against.