I mean, that observation that you need cultural homogeneity (the most charitable version) is simply wrong. Switzerland has been multi cultural for hundreds of y

I mean, that observation that you need cultural homogeneity (the most charitable version) is simply wrong. Switzerland has been multi cultural for hundreds of years and continues to be so, the US hasn't seen a civil war in a similarly long time, thinking of china or india as culturally homogenous is silly and on a larger scale, the roman, byzantine and ottoman empires were stable internally over stretches from decades to centuries. The root cause of strife isn't hetereogenity, it's lack of institutions and mechanisms to resolve strife without violence.