Well you can't eradicate Native American's outside of THE AMERICAS.
I'm not denying its horrors. Not in the slightest. But I'll give you that...didn't it happen in JUST North America...no.
Japan wasn't allowed to have a standing military since then. So basically they dived head first into RAPID industrialization even more so than during the Meiji era. This was mostly done to supply western powers with raw materials. Literally their recovery after WWII is called "The Economic Miracle". They worked their people to DEATH. Even now in the business world the Japanese are absurdly hard working. Combine that with a strict honor bound culture and you have a suicide rate that's massive and a de-emphasis on mental health/wellness.
Also, their popular culture for the 40+ years after became obsessed with dystopia and post-apocalyptic themes. Japan is only place on earth to get nuked. In their eyes, they've already seen "the world end". If you look at most of their creations most forms of entertainment until the 90's were rooted in the pre-Meiji past or far future. Very little outside of kaiju films were contemporary...and even those were about nuclear fallout. There's a block of Japan's history from 1945-1970ish that they simply just don't talk about.
What happened in Japan's history from 1945 to 1980?