People in the US from other countries have often assimilated at least some US culture. Or will be expected to assimilate important cultural issues more rapidly in an office in the US with mostly US cultured people than in an office elsewhere with few US cultured people.

Many of the communication problems are rapidly addressed with constant realtime communication that happens in a shared office but doesn't with teams working separate hours.

There's also a big difference between one or two people from other places on an American team, which will still behave like an American team, and a team of people entirely from country X, which will behave like a country X team.

Exhibit A: https://www.cnn.com/2020/07/01/tech/cisco-lawsuit-caste-disc...