The word civilization is not a pejorative, but merely a label. I am sure you know that it denotes a society that has reached a certain level of cultural, technical and societal development. How is that insulting to anyone anywhere?
If there are ancients ruins in sub-Saharan Africa they would be easily visible; building stones produced by skilled stone masons are not easily over looked. Nature does not produce large rocks of uniform size with smooth sides and square corners.
Look up Great Zimbabwe and be educated....
African Empires , like European and Asian ones have risen and fallen - Mali, Songhay, Ghana. By Great Zimbabwe I believe you are referring to the Kingdom of Mutapa which I think fell under early European colonialism.
Not all Africans were running around the jungle chucking spears and beating bongo drums - they had some admirable civilizations - some which probably sent expeditions as far as the Americas.
That is partially true the Negroid peoples of Africa south the Sahara did have their share of kingdoms and empires, but I have seen no evidence of civilization. It is not necessary to have a civilization in order to have an empire. The Comanche Indians of the US southern plains had an extensive empire but no elements of civilization.
I would like to digress a little say some against civilization. Some people give a positive connotation to the word Civilization so consider this: A sadistic slave master during the early Roman empire could openly purchase slaves for the sole purpose of raping and torturing to death. And if the slaves rebelled against such treatment the entire household of slaves ,regardless of guilt, would be crucified under Roman law. To me that is not positive, but horrible, despicable and disgusting. That it is only one of the negative attributes of the ancient Roman civilization.