I'm not hugely educated in this but I heard a theory that many Western blacks (descendants of slaves) do have a legitimate claim to the ancient Egyptians. Yes many slaves are of West African descent, however it is widely accepted that many tribes were selling out each other to European slave masters at the time for no gain.
the theory I heard was that around this time in history, after the Romans had made many Egyptians flee South, Persian and Europeans followed them into southern and west Africa but couldn't distinguish between them and other blacks. Tribes from these areas could! And sold Egyptians out in their thousands.
just a theory. Seemed plausible.