He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you.
However, I contend there is an enormous moral difference between intentionally cutting the throat of a child and accidentally killing a child while attacking legitimate military targets.
However, I do think Americans are sometimes too accepting of a high level of collateral damage. As long as its our enemies, not us, who's being damaged.