I know they viewed it as preferable to the Islam or traditional beliefs which dominated neighboring regions of Africa, as shown by Portuguese assistance against invasions by Muslim countries, but did Catholic and Protestant colonists view Ethiopians as practicing "the wrong kind of Christianity" or something? Did their send missionaries to Ethiopia to try to Europeanize their Christianity?
Although it is a few centuries early for your question, I enjoyed /u/Compieuter's answer to What did European Christians in the Middle Ages think of Ethiopia, and vice-versa?.
There is also the FAQ on Ethiopia which has a few answers on colonial powers and Ethiopia.