It is the average. Of course there is variation with some high IQ blacks. Americans are afraid of a biological basis of intelligence as it directly threatens their basic false belief that we are all equal. We are equal before the law(a now dubious assumption with “equal opportunity” and diversity.)
I don’t believe we are all created equal (the Bible doesn’t say we are); I just don’t believe the inequality stems from genetics/race. As for affirmative action, it states we are NOT equal in the eyes of the law, and is a de facto acceptance of racial and gender inferiority by the government.