Were Paul Tibbets, Truman, men who flew raids on Dresden and Japanese cities, Charles Sweeney all murderers? Or were they people giving very difficult orders and/or carrying out missions that look horrible but probably saved many more lives in the long run?
Robert McNamera, as one of those who planned the bombing missions over Japan effectively admitted that by most definitions he was a war criminal for this. And by his account, his companions all, on some level, knew and agreed with this.
Many people seem to look poorly on this. I have a different take. Its a big sacrifice to do something that might objectively be looked upon as wrong but do it anyway because you are doing it for your country, family etc. Sacrifices come in many forms beyond the obvious physical ones.
On the same vein, there's an anecdote I heard where, sometime after the war, Oppenheimer met with Truman and discussed the morality of using the bomb. Oppenheimer expressed his guilt and that he had "blood on his hands". Truman supposedly replied with something to the effect that he was the one who had to live with giving the order. Given he later called Oppenheimer a cry baby scientist, I suspect Truman had his own guilt to live with thereafter.
I'll defer to higher beings on matters such as these.