Of course there were never any atrocities in Japan, or from Japanese soldiers right Akuma?
There are many many Japanese ex-patriots, large populations, who live in the US, Brazil and other countries who 'mix' just fine.
They usually left Japan due to the rigidity of Japanese society. And we know that trees that don't bend break eventually. Japan may resist integration but the homogenization of mankind is an inevitability
The winners get to write history, which is why you learn English in school in Japan!