He makes some valid arguments. Evolution is about group conflict. Every group naturally defends their group.
Why were Africans brought here? They were brought here for selfish reasons. The same reason as why we need open borders. There are some in our business community who desire cheap labor. These are men who strive for individualist aims. We need the immigrants we are told to do the work that Americans are not willing to do. Besides getting the dirty jobs done it is also a benefit, we are told, because it allows us to be more 'competitive'.
This is the argument of the economic man. The economic man is an individualist who rationalizes that individual profits, or in the case of the slave master or plantation owner, takes precedence over our biological roots that we have evolved from which originated from the first homo sapiens, the Nordic man who is epitomized by the term 'hunter-gatherers'. The hunter gatherers were a tough breed of men. They and only they knew how to live and survive in the cold Arctic climate of the Ice Age that took place in Northern Europe and Russia. The Nordic Man was tough. He was physically big and learned how to use tools. He knew the value of community because cooperation with other Nordics was essential to survival. His woman was the homemaker and was his opposite. She was feminine and took care of his manly needs of cooking, cleaning and bearing for him strong and healthy like minded descendents. Without those descendents, the tribe would perish. For those who were strong and knew how to survive, they continued on. Ingenuity, strength and securing a foothold in the Ice Age was of primary importance to these earliest of our descendents. If one was a freeloader, not willing to work together for the group, there was punishment. Altruism, or sacrificing individual interests for collective interests to sustain the group, was a necessary ingredient that led to progression.
As the Ice Age receded and climates became warmer, farming and collective feeding then paved the way for a weakening of man. There was no need to be a hunter gatherer to survive. Food was more readily available for the freeloaders and thus we saw an increasing in demand of the Middle Eastern man. Verbal skills and commerce developed a need for middlemen or traders. Group or collective necessity was replaced by other forms of altruism. The men became physically smaller and the women began to look more like the men. Individual interests eventually replaced the collective interests of the Homo Sapiens.
Add to the effect of population mixing, the advent of Christianity and Western ideals and man then went through the Enlightenment. Men were judged by objective ideals and with Christianity began to welcome everybody. Group interests were replaced by individual and, shall we say, business interests. If it is good for commerce, then that is the overall good. That was the mindset of the slave owners. They didn't care about the consequences of this strategy on the group's interests or what would be the result for their descendents. With the new Western ideology of accepting all man as equal and not enforcing group goals or even caring if there should be such a thing as a group, which became pathologized as we see today in modern liberalism, we now see every group now demanding their own group goals.
So, there are legitimate grievances, but it is also a story about a failed strategy for one group and how it failed from an evolutionary standpoint. The Western man became a libertarian, an individualist, for himself, the plantation owner. And now we suffer the consequences. Likewise today, we still hear about the need for Amnesty, or how it is termed in a Egalitarian sense 'Immigration Reform'. Yes, we feel sorry for the illegal immigrants who are here because we are a civilized Western people. We are prone now to allowing any group to come in, throwing out all group or collective interests to preserve the land, for the sake of all humanity. Thus, we've left ourselves open to insane immigration policies for the so-called betterment of humanity. What we see again with immigration, as with past slavery, is a continuation of a market set of ideals which contrast sharply with the healthy goals of the earlier hunter gatherers.