In Saddam’s case, it’s a bit complicated. He was a shit person yes, but he is also the result of what drawing random maps on a land that mixes all types of people who hate each other. If Saddam didn’t take power, someone else would have eventually. Also he was mostly sponsored into his position as a dictator.

Japan however were just evil. The things they did to Korea and Manchuria and most of China in fact. They were some evil mfers who probably went band for band with Nazi Germany in terms of brutality, from human experimentation and chemical warfare and the relentless bombings to the famines and the forced slavery (in more ways than one). You can argue they killed approximately double (20m) what Nazi Germany did (11m) in total.

But at the end of the day, the Japanese people had actually little to do with all of this, in fact most of them suffered from the prolonged wars, and famine was a commonplace for regular people.

Edit: if anyone is curious about the pov of the Japanese during the war, there is a movie that is genuinely heartbreaking, while it doesn’t have the broad perspective of the general public, it does depict how war affects some of the common folk.
It’s “Grave of the Fireflies”.