"I doubt it makes a difference to the populations affected whether they were an intentional target, or the gps on the smart bomb that just leveled your house glitched out."

You're wrong.

If an airliner (or even a weapon) goes astray and kills my family, I am going to be angry, no doubt about it.

If you've deliberately targeted my family, my anger is going to be greater by several orders of magnitude.

For example, this case that was in the news today:

http://www.startribune.com/lifestyle/156366185.html

Suppose the phosphorous did get there through some type of negligence on one of the nearby bases (seems plausible, at least).

Are the woman and her family going to be angry? You bet. Are they going to file a monster lawsuit? Almost certainly. Are they going to declare war on the United States, or (try to) kill a few Marines? Not a chance in hell.

Intent matters.