// This is of course where jims argument fails. Why would Black Africans want ethnic superiority over other blacks? //
The problem with suggesting that my argument fails is that again you're assuming a narrow definition of racism that can only apply to White people. I've explained elsewhere why this is mistaken. The focus in the UK is on the racism of White people because of obvious historical reasons, but this is to mistake focus for exclusion. Clearly there are examples of racism, and slavery, throughout history, perpetrated by any powerful group over some less powerful one. But this doesn't undermine the idea, at all, that slavery is an economic solution to a racial/superiority complex.
I can see the point you're all making, I think, but it still seems like you're framing slavery and racism as "how can I justify this economic decision?" -- and that is a mistake. What comes first, always, is the power dynamic. You cannot enslave a people unless you have defeated them in battle, or controlled them through some other means; and you would not enslave people you did not respect as equals. Slavery is a condition that denies the humanity of the victim.
Hence, also, the utter fallacy in "demonising the White race they despite" -- at least from my point of view. I can't claim to speak for anyone else. But this isn't about some white guilt complex.