Well, that's a bad example because there've been dozens of papers regarding strategic bombing in WWII, and almost all of them concluded it was a failure as far as affecting production capability of the bombee, and a worse failure as far as morale.

So on the efficacy front, it didn't make sense, and on the honor front it's on some pretty shaky ground. Of course, it happened, so there's that.

It's one thing to say that it's ineffective to bomb residential neighborhoods. It's another thing to say that it's always illegitimate. Also, what about factories staffed by civilians producing ball bearings or tires?

Or, in more recent conflicts, attacking truck drivers, weapons system maintainers, UAV operators, base entry point security guards, drivers/security for intelligence agencies, etc. At the very least, this forces the military to devote more resources to force protection for these contractors; it also limits operations out with the populace, and drives a wedge between the occupying military and the civilians in which the insurgents can survive.

And also there was a lot of resistance to targeting purely civilian areas especially early on. Later on Germany did specifically terror raids Coventry for example.

But even hamburg was a major center for the support of U boats so you can see why the threat of the later Elektroboote Tpe XXI boats would put them on the target list.

Oh and my Fathers house was hit by a bomb - but they where going for the Largest Spitfire factory in the UK so it wasn't his house they were trying to hit.