Saying that pizza is European isn't necessarily wrong just as saying this man was African isn't wrong. I agree that it is not very specific or precise but it is just a broad title meant to attract a broad audience. Furthermore, Malik Ambar wasn't necessarily Ethiopian, in the modern sense at least, so what would you call him? Calling him Oromo could have a negative effect (views wise) since not that many people know who that refers to.
Africa is the most diverse continent even with excluding all the foreigners (the Arabs in North Africa, and other parts of Africa, and all the cadaans) but as native inhabitants of that continent, we can all be referred to as Africans. It doesn't mean that we are all the same it just means that we share a continent.
If you don't mind i will add my piece to this. In regards to your Ethiopian point, that could used to mute the point of him being African. Firstly because that term was first used to describe North Africans. It was only till the Trans Atlantic Slave Trade that the continent was referred to as Africa. Historically as only parts of the Maghreb were called Africa. The term was used to define a land mass that historically and culturally had no name for a long time. Whereas with the term Ethiopian, it was used to identify the northern part of Sudan and the Southern part of Egypt. Yet there is great debate to how far the region was. If you asked Ethiopian scholars ,some falsely, would argue that it was modern day Ethiopia and if you asked more trustworthy ones, the will inform you that the Ethiopia region was used to describe everything south of Egypt, just as other scholars who are familiar with the region would suggest aswell.
Whereas the Term Africa has only be popularised in the last century or so. It would have been far better to call him Ethiopian than African as it at least it has more of an profound connections to the region he comes from. The issue walaal is that the term African shuns the diversity of Africa, it doesn't enhance it. How can one identity that has no real grounding historically and culturally be able to encompass and emphasis the individuality of some many different people. By explicitly calling him African you strip of his culture, his identity and what he is and ascribed him to a notion that doesn't represent him in slightest. It is being intellectually dishonest and untrue by identifying him to something in which is not a true represent of what he is. When people who are unaware of the true diversity of africa see the title, they will think that he looks this
When in actuality he looks like this
