In the south, we had black methodist churches, black baptist churches etc. They never integrated and still are much separated. It seems to have been a pronounced cultural pattern. I don’t think the Mormons were alone in it.
except the Catholics. Even today, a very mixed congregation, even in the most affluent parishes in my releatively affluent suburb here in the middle of the country.
I live in GA. We have Hispanic and Black families that attend our predominently white church. Our pianst is a lovely black Christian woman. This church was built around seventy-five years ago. It is nice to see that things change with time.