BTW, labeling something 'military target' (pretty arbitrarily, in this case) does not give one a moral free pass; indeed, it's only a particularly poor attempt at justifying whatever.
No the justifying comes from the fact that it was either this or an invasion of Japan, and considering how most attacks on Japanese held territory in the war went that WEREN'T their country it's safe to say such an invasion may have been a blood bath on both sides.
And in this case its justifying it as the lesser of two evils.
this is historical myth. Japan was already on the verge of conditional surrender by the bombing of Hiroshima, they were using the USSR as a go-between. What they were concerned with was the preservation of the emperor. Dropping the a-bomb was about making sure that it was an unconditional surrender and it was about intimidating the USSR with what America could do. Either way, an invasion of the homeland would not have been necessary. And if they had needed to use the atom bomb, a demonstration in an uninhabited area could have been made.