Well, if as Christians we still pay attention to a certain insignificant differences as the accent or dialect, the color of the skin, the facial differences, and other physical or cultural aspects of a person, we are not truly in Christ.
Yes, Christ made differences between Jews and Gentiles, but He made it on the basis of GOD'S selection, responsibilities, and Law, not on ethnic and cultural differences.
Acts 15.8-11
8.And GOD Who knows the human heart testified to them (Gentiles) by giving them the Holy Spirit, just as He did to us,
9.and in cleansing their (Gentiles) hearts by faith, He has made no distinction between them and us.
"He has made no distinction between them and us." This means that those who has Holy Spirit of GOD in their heart and cleansed by faith, all absolutely equal in GOD, no matter what the race of a person is, culture, or traditions, and if a race in this case no longer exist, this means that all so called "ethnic and cultural" aspects are erased as well, all became one in Christ.
Galatians 3.28
28.There is neither Jew nor Greek (Gentile), there is neither slave nor free man, there is neither male nor female (Matthew 22.30) (Mark 12.25) (Luke 20.33-36) (Galatians 3.28), you are all one in Christ Jesus.
We also know some examples of Jews and Gentiles who intermarried and have no problem with so called "ethnic and cultural" differences; Rahab, Zipporah, Ruth and some others, they are all became the part of Israel and considered as native Israelites, and all belongs to GOD of Israel.
They do not need "Christian" counseling Salty, they need Christ, and then they get Christ, then they will be one in Christ.