Hamburg, Dresden, Tokyo, Hiroshima and Nagasaki targeted and killed hundreds of thousands of women and children in a most horrific manner.
I’m not saying I wouldn’t have done it - but the military justification, which was to terrorize civilian populations and collapse support for the war, makes the wide-area firebombing into a “military target” in only the broadest sense.
Contrary to other leftist delusions, Hiroshima and Nagasaki were military targets. There is plenty of evidence in military documents now available on the internet. In his The Making of the Atomic Bomb Richard Rhodes discusses Hiroshima as a military target (pp. 626-7) and Nagasaki (pp. 392-3), which had the Mitsubishi Munitions plant making torpedoes.
Also, civilians working in military sites and in military areas were warned to leave. If civilians specifically were to be targeted, the atomic bomb could have been dropped in a different location, especially in Nagasaki, for a higher civilian death toll.
And if the United States had developed the atomic bomb six months earlier, it is possible that the German military target, Dresden, would have been destroyed in a nuclear blast rather that destroyed by firebombs. Again, in war, that would have been completely and morally justified. In fact if Truman were to have decided against using the bomb, he would have been a traitor to the United States.
Of course some of the Allied bombing did hit civilian areas with no military significance. The Allied pilots (many who died trying) would have preferred to accurately bomb military manufacturing plants, oil depots, railroads, bridges and ball bearing factories, and repeatedly tried. But with factories and rails near some residential areas, obscuring smoke, poor accuracy, and occasional interference from the Luftwaffe and anti-aircraft flak, residential areas were sometimes hit with bombs.
Perhaps some would like the widows and orphans of Allied bomber pilots killed in Germany to send sympathy cards for the misplaced bombs of their husbands and fathers.