I know there are plenty of conflicts and propaganda designed to make the enemy appear evil. But typically, wars are in a very gray area. Everyone agrees it's awful, horrendous, etc. But typically, there are numerous and multiple sides to the conflict and that's why it's gray. Because each side has an agenda, has a motive, has an ideal -- that it's fighting for that others in the world may side with.
But it seems that pretty much the entire world at the time as well as moving forward went "yeahhhh no, Hitler is very clearly evil." It never seemed as straight forward as it did with this particular war. The Japanese side of things is muddier -- not everyone viewed them as evil in the same way they did Hitler and there's still some controversy over the bombings of Hiroshima and Nagasaki afaik.
So is this just a skewed interpretation? Was it far grayer than it's usually implied? Even if more morally gray and less universal, is it the war most people at once agreed there was one group that needed to be stopped? And lastly, were there any other wars that rival that level of gray-ness?
The narrative as presented in your question is very much an over-simplification. I'd have to say that to many the Japanese were much more "evil" in terms of public opinion than the Nazis at the time of the war. I even heard once that the national collegiate debate champion teams in one of the years '39-'41 won with the proposition that the US should enter the war on the German side, although I've never been able to back-check it. The Japanese, meanwhile, were seen as absolutely brutal for the Rape of Nanking and the invasion of China during the 1930's. Hitler was just another German starting a war on the Continent, and in fact had been voted Time's "Man of the Year" for 1938, for taking Germany from the brink of collapse to hosting the Olympics in under a decade.
As to other wars, you could probably establish that kind of dialectic for the Soviet invasion of Afghanistan. Chemical weapons, brutal counterinsurgency methods, and near-universal condemnation on the international stage, all against a nation that couldn't have threatened the Soviets if it wanted. Iraq's invasion of Kuwait received that treatment in the press, as it was pretty much entirely motivated by oil. (If someone has a more nuanced treatment of the latter conflict, I'd love to see a good book on it!)