The issue isn't that these things happened, or that they were wrong, but that some of the people sitting on the panels knew their own countries did the same. One of the charges against Goring was the bombing of civilians in London. He is reported to have said he would face that charge if Bomber Harris and Curtis LeMay were up there with him. By trying to make war under the rule of law, you make yourself guilty. Did we target non combatants in WWII? Yes, that was part of the strategy. The British were quite open about (night raids and statements by Churchill), while the US did attempt more targeted raids, but the demoralization and death of the civilian populations was viewed as part of the plan. The thinking was it would end the war sooner.
Under the terms of international law now a days, that would be a war crime. Granted, we have learned that mass bombings do not work that well (and air power as a strategic conventional arm is not that effective period). And we have the means to drop ordinance in a much more precise manner (great for tactical bombing) so the prospect of the US sending out mass flights of B52's to level a city is very remote. But in WWII, it was considered a just application of war.
Imho, it may still be a viable option.