For example?
The early church was ready to schism over when to celebrate easter, not even the Greek and Latin Christians had a really common culture.
The church propers best when it doesn't seek to unify either ethnicities or cultures. It does not more or less than introduces different peoples to the Good news, and lets them celebrate it in their own
The Persian, Roman, Egyptian, English and multiple empires became empires by conquering distant lands. These lands and peoples were all of differing races and ethnicities. The success of maintaining order and peace came from instituting a common culture, government, and language. As evidenced in scripture, Rome allowed the Jews and other ethnicities to practice their own ethnic traditions and languages, as long as they adopted certain civil practices, and did not usurp the Roman rule. In Africa, Jamaica, or India, you can still see the lasting cultural stamp of the English, but the ethnic traditions never really died, even when England ruled.
Pax Romana?
Hellenism?
The sun never setting on the British Empire?
I call that survive and thrive.
The squabbles of the differing ethnicities of the early gentile church had to be tempered by adopting a common BIBLICAL CULTURE. This was one of Paul's lasting contributions to the early church. The different traditions of the various Orthodox churches of the East are a lasting testament to unity of culture, while maintaining distinct ethnic variations. Coptic Christians vs Assyrian vs Armenian vs Greek, etc. all testify to a unity of certain Orthodox distinctives, but variations based on ethnic preferences.
I agree that isolating and segregating ethnicities within Christianity will eliminate a lot of strife, but the sin nature of man will never allow for a squabble free church. The ability for races and ethnicities to unify under the umbrella of Christ has been a lasting testament to the power of the Gospel.
I am not a member of the majority race or ethnicity in the United States. Would you refuse my membership in your fellowship so that I can celebrate it in my own way and not have to interrupt your culture?