[rayiner]

If you compare like with like, the US is more diverse on almost every dimension except language. Catholic/Protestant is a major dividing line. And if you are going to say “white” is a category, then Singapore is virtually 100% “Asian.” If you want to talk about ethnic groups, then the largest US ethnic group is German Americans, which are only about 25% of the population.

And yes the homogeneity helps Singapore’s orderliness. The overwhelming majority of the population is Asian, who in general are more collectivist and orderly than say Italians.