Well-defended? Is that some sort of joke or something? If those bombing raids were so well defended, why were thousands upon thousands of German civilians being killed in single raids over one city?
The extent to how well German airspace was defended can be seen in two ways.
First, a specific number: in September of 1944 there were
10,225 heavy artillery pieces used for aerial defence of the Reich. Indeed, the need for ever more guns pointing skywards to protect against bombers meant the German army was starved of anti-tank artillery. Albert Speer himself stated that of the
19,713 dual purpose anti-tank/anti-aircraft 88mm and 128mm guns produced between 1942-44, almost 84%—
16,541 guns—were assigned to aerial defence. That left only 16% to go to the army for the anti-tank role—this no doubt greatly helped the Allied ground campaigns in both the east and west since they faced far fewer anti-tank guns than they would have otherwise.
Second, general data: look at the number of Allied bombers and crews lost during the bombing campaign. As a proportion of the fighting force, the losses were huge. You don't have those types of losses against undefended airspace.
If bombing war material production facilities was the only goal, why were we also bombing civilian housing? Why were we dropping mixtures of high-explosive and incendiaries, which we knew could create uncontrolled firestorms?
The reasons should be obvious: a worker whose home has been burned down has to be found new accommodation—that requires time and effort on the part of the government. Streets and roads are blocked with debris, thus hindering general economic activity. All that damage has to be cleaned up and repaired. This siphons off economic effort that would otherwise have gone directly into war production. Granted, this is not as direct an effect as knocking out a tank factory, but the indirect effects do matter.
There is also a very practical reason for aiming at the built-up areas of a city: because that's about all that can be found and hit successfully at night. And that was the case for well into the war.
The mix of incendiary and high explosive bombs was determined by trial and error to maximize the spread of fire since fire was a very effective way to destroy buildings. And destroying buildings was the point of the exercise. Because the more that is destroyed the more that has to be repaired. And any effort spent rebuilding workers' homes, repairing broken water mains, restoring rail and tram lines, clearing the streets of rubble, etc., means effort that is not spent on war production. That matters in the long run.
Nobody is saying civilian populations could have been completely spared from the effects of war, but they certainly could have been spared from having their houses bomb.
Considering that bombing accuracy at night was measured in miles, even the best effort was going to clobber plenty of the surrounding area. A blunt tool, as I said before, but the only tool with the means to hamper German war production. Things were better in the daytime since accuracy was better—but only when the weather was good. When it was not, things were little better in terms of accuracy than they were at night. Such was the technology of the time.
None of this is an excuse for deliberately bombing women and children. Soldiers should never be directed to fight civilians. They should only be directed to fight other soldiers.
No civilians, no economy; no economy, no military; no military, no war. Feel free to cite the error in this statement as it pertains to war between industrialized nation-states. It seems you simply do not appreciate the way in which the entire national economy was directed to the war effort.
