If when US citizens are killed by those who consider themselves at "war" with America it is "murder" but when the US kills people it believes it is at "war" with it isn't murder
Really? You don't see the fundamental asymmetry in what you've just described? When a militant attacks the US, both the militant and the US agree that he's at war with the US. The militant is happy to tell you and the US is happy to take him at his word. But the people the militant is usually attacking - American civilians - aren't at war with anybody. And that
is murder.
Killing a soldier, on a battlefield, during a war isn't "murder." Killing a civilian during an attack on a soldier is a regrettable accident, but it's not murder either. Killing a civilian on purpose
is murder. We're not the ones who do that. The people we're trying to kill are.