World War II was the exception rather than the rule. Prior wars did not have similar levels of civilian destruction. World War I had some, as did the Franco-Prussian War, but mostly executions for francs tireurs.

That was purely a matter of technology. Prior to WW2 strategic bombing did not exist. Plenty of old wars were famous for the mass murder of civilians, such as the 30 years war. Back then, if you wanted to kill civilians, you had to get your hands dirty. It was because of wars like that that Europeans finally started to realize that mass murder of civilians was a terrible and unnecessary thing, and to work towards imposing a taboo on it.

WW1 had chemical weapons. That was a lesson learned well enough to prevent their use in WW2, even during Götterdämmerung. WW2 had strategic bombing, the excesses of which led the west to impose considerable limits on it after WW2, as seen in Korea, Vietnam, the Israeli wars, etc.

They were using incendiary bombs, intended to set the whole city on fire. So what 'general area' is that? The population center, of course.

All WW2 bombing had some incendiaries. It just made since to do so since the idea was to use regular bombs to blow a structure apart, and then incendiaries to light the exposed material on fire. Dresden had a mix as usual The only time you can truly say the goal was to create a firestorm was the firebombing of Tokyo, where the bombers overwhelmingly carried specialized incendiary cluster bombs.

Didn't Truman's diary say about Hiroshima that he was comforted by the fact that at least it was a military target? One wonders what the military told him.

Politicians lie a lot to make themselves feel better. Technically you can call any city a military target since they all had factories in them. The purpose of the nukes was to break the morale of the Japanese leadership and it worked exactly as intended.

What if I'm in a plane and I try to bomb a civilian area? Seems like a lot of people try to exculpate those who rain down death from the sky.

This happened plenty of times, most notably with Germany doing it in a very openly intentional way such as with Poland and later Coventry, the London Blitz, and much later with the Baedeker blitz. The Allies told themselves that they were morally superior, and to come extent they were, but they also sometimes crossed the line, most notably with Dresden.

And FYI I agree with Winston Churchill that Dresden was primarily a "terror bombing". Churchill wrote on 3/28/45: "It seems to me that the moment has come when the question of bombing of German cities simply for the sake of increasing the terror, though under other pretexts, should be reviewed. Otherwise we shall come into control of an utterly ruined land ... The destruction of Dresden remains a serious query against the conduct of Allied bombing."