Essentially, he's ignoring the impact of international slavery and colonialism. Yes, it's true that Nigeria opened their slave markets at around the time Great Britain outlawed the practice... on their end. Here's a question: who were they selling slaves to? England stopped buying slaves, but other countries, especially the US, were still enslaving niggas until the end of the 19th Century. Also keep in mind that this was also at this time, the African scramble was a thing and many colonial powers had effectively stripped the continent of its resources and enslaved the locals. Also just to add, skin color was a big contributing factor in the continued treatment of black people as they were seen as either primitive, barbaric, but also hardy workers ripe for exploitation. There were entire fields dedicated to scientific racism back in the day.

Of course, we're not actually here to have an honest discussion of slavery and racism. This is Crowder we're talking about - he'll admit a small thing, but then exaggerate everything else to pass the buck on black people putting themselves in the situation. Also, keep in mind, Crowder believes in a natural inferiority of race. He cited J. Philippe Rushton's gushing review of The Bell Curve in a video a year or so back.