he is partially right about some Northern Africans not being black,but it is not ture there was no black populations in Northern Afric,because there was and still is. THe black populations in Northern Africa are the afer,which was described as black by roman accounts,Garamantes were black and related to the tibbu in chad and niger.
Tuarege are not white and they are actually related to Beja tribe in Sudan,and are black.
The only non blacks in Northern Africa were the coastal type berbers,around places like tunisa,but for the most part the sahara,southern algeria,southern morocco are black and always have been. I recommend oomen you check out the work of COlin P groves,and shomaka Keita on this issue.