The threat of Japanese people all waging guerrilla warfare was considered real enough that the US decided to keep the Japanese Emperor as figurehead (even though the US had enough power to sentence or even execute him for war crimes), just so that the Emperor could order his people to surrender and obey US forces.

Something the current US regime might have forgotten.

Yes, hence the continued US occupation after WWII, among other countermeasures.

Israel has been killing iranians for quite some time. Here are some notable examples from the last twenty years or so:

https://en.wikipedia.org/wiki/Assassinations_of_Iranian_nucl...

Germans were salty about being bombed and Germany destroyed. They were also occupied for years and also victory forces made sure the victory was absolute - no peace agreement but armies everywhere. There were other aspects too - like nazi doing a lot of destruction of the Germany by themselves. Germans back then seen the whole thing as a tragedy for Germany and Germans.

The rebuild phase where allies put a lot of effort and money into rebuilding Germany did a lot to ensure good result there. And you still see fascists being popular in Germany, especially in former easter block. It is just that everyone else is still traumatized by the past, school system make sure everyone knows past and nazi propagation is literally illegal.