Absolutely. The author is WAY too hung up on the phrase as some kind of holdover from colonial-era European writers using it as a pejorative to mean "uncivilized", when now almost anyone you'd ask would interpret "pre-colonial" as meaning, "before the racist, white supremacist European assholes invaded".

If someone is actively using the phrase to homogenize African cultures or treat pre-colonial Africa as a monolith, call them out for the homogenization; people do that with "post-colonial" Africa too.