I don't agree with all of Dr. Walker's positions (some Egyptians were certainly black), but his point that it shouldn't matter it true (Egyptians had no conception of race as we understand it). His attack isn't on the existence of Afro-centrism, it's the fact that oftentimes Afrocentric scholarship denies historical fact.
The guy in the video mischaracterizes criticism of his book, as the author did often throughout his career. His book was universally rejected by MesoAmerican scholars. I'd encourage you to read the JSTOR article (if you can't access it I have a subscription and can PM you the text). They debate the evidence more articulately than I ever could.
In the video he does make several good points (along with being a very engaging speaker who gave a great narrative on Haiti), especially about Wilbur Wilberforce and freeing the slaves. I'd recommend reading
Moral Capital by Chris Brown at Columbia if you want to know why English abolitionists were for freeing slavery (hint: it wasn't out of the goodness of their own hearts as we are often taught)
Christopher Brown - Faculty - Department of History - Columbia University
Also, his point about learning more about Henry VIII than massacres and slave revolts is ABSOLUTELY true. It's ridiculous, and I agree with him, and his people, centered, global approach to teaching that he proposed is inspiring. He is absolutely correct. History is absolutely whitewashed and its absolutely bullshyt. World history should be taught, and people of color need to be included.
But (and this is important) we need to remember that we need to stay within the REALM OF FACT. This means that we need to evaluate evidence as it exists, and not get carried away, because if you do that, logical people no longer take you seriously. Here is where he messes up. He is so eager to assign agency and importance to certain people groups that he makes huge leaps and picks and chooses certain strands of evidence out of context to bolster his argument. Here is another article discussing Van Sertima's book that discusses this published by an accredited historical journal by three professors. Hell, just by reading the first paragraph on the preview you begin to get an idea.
Robbing Native American Cultures: Van Sertima's Afrocentricity and the Olmecs on JSTOR
Keep reading from there.
Ultimately, his heart is in the right place and he obviously is an intelligent guy. But his agenda, in my opinion, is blinding him to practicing history correctly.
But let's put it this way: I would MUCH rather have a guy who errs on the side of Afro-centricity than the opposite : a historian who constructs narratives that bolster white supremacy. Both are wrong and need to be addressed, but one is much more harmful.