A national team should only have players from their country's ethnicity/culture.
By the original meaning of the word “nation” that statement is redundant. It originally meant “a race of people, large group of people with common ancestry and language”. We’ve reduced it to the same administrative meaning as the word “country”, a geographic, legal, and economic zone.
I don’t think that happened by accident. (((Someone))) doesn’t want us thinking of our countries as the homes of our racial and ethnic groups.