Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
Culture should be embraced, ethnicity should be celebrated, but chauvinism is wrong in any instance. There are also shades of grey. For example, the Ethiopian Church gets accused of phyletism but many times it is precisely the opposite, the emphasis on cultural and linguistic aspects of the Ethiopian jurisdiction were not intended to elevate one ethnic group in Ethiopia above another, rather like Latin in Europe was to serve as common denominator and bridge.
Amharic and Ge'ez as languages and other cultural aspects of the Ethiopian Church are organized and centralized to encourage a more Universal approach to the Church, which can embrace more peoples under single banner. Amharic or Ge'ez is not the language of all Ethiopians, but they are the languages of the Ethiopian Church. The cultural aspects of the Church (which are not exclusive Amharic, rather a syncretic blend of Tigreyan, Amhara, Agew, and Shewan-Oromo cultural) are intended to offer a universal platform and commonality to the Chuch, rather then to encourage an increasingly splintering of ethnic Christianity. Today the Ethiopian government has been experimenting with the concept of Ethnic federalism, which has proved largely a disaster. Thankfully in practice the Ethiopian Church has essentially been the opposite. Yes, many folks have accused the Church of chauvinism or even Phyletism, but these are just hating. The Church has done her best to alleviate these matters in a way which is mutually beneficial to ALL parties involved.