@NotVerySmart wrote
I never said Latvians & Estonians are ETHNICALLY homogeneous; I said they are RACIALLY homogeneous. The last time I was in Latvia, I didn’t see any but White people.
It’s a red herring that a group has to be integrated in the larger community for their kids to be a academically competitive. Stuyvesant HS is full of poor immigrant students, notably lots of poor immigrant Chinese students living in ethnic ghettos like Chinatown, and poor Russian immigrants.