That's the difference between bombing, say, a munitions plant versus a mere population center. Dresden has always been less defensible in my mind than Hiroshima, and by a good margin. Nothing was manufactured, nothing produced, at the WTC. It was an office building, and I doubt most of the highest executives were there at 9AM on a Tuesday morning. I'm reminded of the guy who told his wife he was going to work when he was really going to his mistress; if he hadn't worked in the WTC, and it hadn't been 911, he'd have gotten away with it.

A lot of things have been done for millennia; it used to be common practice to kill all enemy men above the age of puberty, rape the women so they'd have the right color babies, enslave anyone left alive, then salt the ground on your way home. It's now considered genocide several times over, multiple war crimes. Hell, denazifying Germany probably qualifies as "genocide" by current UN standards, which is pretty scary. Deliberately killing thousands of civilians just for the sake of intimidation isn't war, it's terrorism, unless, like Islamic militants, it's not even for the sake of a negotiated peace. Then it's just plain old mass murder.

And while it may have been a while, sidebars have never intimidated me, but I'll accept a truce if you wish one.