As far as the Hiroshima example goes:
1. The Japanese had dispersed a significant proportion of their military production through the use of small, home-scale factories and workshops. Other, non-production activities in support of the military were also conducted in the homes of non-military Japanese citizens. The end result of this was the serious blurring of the distinction between military and civilian persons in the population of Hiroshima and other Japanese cities by the final months of the war. As a practical matter, it was not possible to distinguish a “civilian” from a “soldier” in Japan by 1945; the entire Japanese population was directly or indirectly engaged in supporting the war.
2. Hiroshima as a target is notable only for the novel nature of the weapon used to destroy it. The people killed during the spring 1945 non-nuclear firebombing campaign against Tokyo and other Japanese cities were no less dead than those killed by the atomic bombs in Hiroshima and Nagasaki.
3. It is probably always wrong to kill innocent people, even by accident, and even in time of war. However, the alternative — surrender in the face of aggression — is likely equally evil. I have therefore always held it as a matter of faith that the Just Judge will forgive those soldiers, sailors, and other fighting men who have (without ill intent) taken innocent lives in their effort to defens the innocent from an aggressor.
I agree. (You seem to have read "The Making of the Atomic Bomb.")