Low IQ is a result of lack of colonisation. IQ isn't biological.

Even Europe was colonised, by the Romans.

Unlike you and leftist SJW types, I'm not racist, so I don't go looking for easy "color" based answers. The answer is simple : Colonisation brought agriculture. Agriculture is the reason we have an advanced society today. The Americas were turned from the traditionnal tribal hunt/gather society to sedentary agriculture based society it is now through colonisation. Africa didn't get that luxury.

Remember : the modern human species is 300,000 years old. Our modern societies evolved from 290,000 years of hunt/gather traditions to iPhones in only 10000 years because of agriculture. Without it, we would still be living in mud huts, picking fruits and killing animals.