It's true up to a point, but there's also a lot of evidence that multi-ethnic societies don't work very well. See e.g. Alesina and La Ferrara, 2000. "Participat

It's true up to a point, but there's also a lot of evidence that multi-ethnic societies don't work very well. See e.g. Alesina and La Ferrara, 2000. "Participation in heterogeneous communities" or Alesina, Baqir, and Easterly "Public goods and ethnic divisions" or Putnam "E Pluribus Unum".