It was left alone at the Scramble for Africa
Together with Liberia, Ethiopia (then Abyssinia) was untouched at the so-called Scramble for Africa initiated by the Berlin Conference of 1884. When the European diplomats carved up the territories north to south, Liberia was left because it was seen as a colony of the United States but it is not quite clear why Abyssinia was untouched.
Some have theorized that Ethiopia benefited from a sort of respect accrued thanks to its ancient prestige. The land of Abyssinia was known to European historians and so were its mystique and myths, not to talk of Abysinnia’s connection with Christianity.
This theory may have some merit. As far back as the 14th century, the Zagwe dynasty of the Kingdom of Axum in modern-day Ethiopia, sent a delegation to meet a Pope.