Hiroshima revisited: Dropping WMD on populated cities dishonorable way to win a war?

[moderate libertarian]

Recently watched movie Fat Man & Little Boy that is based on US military's Manhattan project. Apparently at the time, some scientists and generals dissented and saw dropping of a WMD on a populated city without warning a dishonrable way to win a war. Do you agree or disagree with such a view?

Little Boy was dropped on the city of Hiroshima on 6 August 1945, followed by the Fat Man over Nagasaki on 9 August. These WMDs dropped on two populated cities by US military killed over 200,000 civilians of Japanese race.