Lets see. WWII, total war across the globe. Millions are dead and dying - the better informed at the time would know that in reality the First world war had never ended it had simply moved across central Asia from eastern Europe.
As the war in the west again broke out - following the Spanish Civil War the pogroms...the Nazis storming across Europe, the war in Asia...
I guess that not having the benefit of cushy hindsight the view was that the war had to be brought to a successful conclusion as fast as possible by any means possible because the alternative was worse.
As I understand it - the Allies were having to kill in an attempt to stop the killing - the Axis powers - if they had won would have continued the killing and the persecution and the extermination.
So we are sorry innocent civilians were killed. But it was war.