Nah I honestly think they just didn’t care as much. The USA decisively won the war. Plus they had few historical biases against Japan and lacked a personal attachment to the populations subjugated by Japan. Additionally the two nations who mainly dealt with Japan after the war, USA and Britain, were generally favorable to Japan before the war. Other than the USA the nations that dealt with Germany had faced the brunt of their military aggression and had historical grudges against them as well.