Lot of people are just stupid. Some might call it low IQ but I view it more as a collection of mental failures: poor reading comprehension, questionable education (specifically on history), poor critical thinking, and a general disdain for education that has led to the previous deficits mentioned. When people don't want basic education they'll go out their way to find information that caters to their pre-conceived notions. That's how people end up believing vaccines are bad, the earth is flat, or (in this case) black people are not from Africa. Or the weird phrenology shyt Tariq peddles. You have to just be so far gone intellectually to fall for this stuff.