The European Colonialists used the Christian religion to subjugate Africans, however, Christianity was in Ethiopia long before Colonialism and the trans-Atlantic slave trade. The Bible tells us that an Ethiopian man of great authority was taught about Jesus not long after His ascension to heaven (Acts 8:27-40). Tradition teaches that this Ethiopian man went back to Ethiopia and evangelised, effectively bringing Christianity to Africa. Ethiopians and the Children of Israel have had a connection since the time that Moses married an Ethiopian woman (Numbers 12:1). Psalm 68:31 states "Envoys will come out of Egypt; Ethiopia will quickly stretch out her hands to God" (NKJV).
The above image is of the Church of Saint George, in Ethiopia. Historians believe that the church dates back to the 12th or 13th century. The trans -Atlantic slave trade began in the 16th century and it took place around West Africa so it had no influence on Ethiopian Christianity. White Supremacists used religion to justify their racist behaviour but it's clear that Africans didn't need their spritual assistance.
Aside from Liberia, Ethiopia is the only African country which wasn't colonised in the 'Scramble for Africa'. The Italians occupied Ethiopia but the Ethiopian people were able to resist being conquered. I believe that the Ethiopian people got their spiritual strength from their faith.