The fact that more than half of all black people tested in the US before 1973 scored under 85, causing the AAMR to actually lower the threshold of mental retardation to <70 so that opponents of the civil rights movement could not use this to withhold equal rights from blacks, and that today black people score significantly higher than they did thirty years ago (although their median score is still not on par with that of whites), and that research by reputable, nationally renowned authorities in the field have proven that there is no physiological, biological, or genetic difference in intelligence between the races... the difference in test scores is caused by cultural and environmental factors.
In fact, the overall average Black-White IQ gap has been reduced by one third over the last 30 years (although the median IQ difference between black and white adults is still 17 points).
The test is racist. The end.
It's also classist and anglocentric/ nationalistic/ xenophobic, as the poor of all races and also first-generation immigrants of nearly all ethnicities score significantly lower than middle-class whites.
If the test wasn't racist, the IQ/ race gap wouldn't have begun closing since the end of Jim Crow/ the beginning of civil rights.
It's not like black people were troglodytes who just suddenly and miraculously began to evolve 30 years ago, and that this miracle just happened to coincide with our decision to make racial discrimination, segregation, and general abuse illegal.
It's only been one and a half (or possibly two) generations since the civil rights movement. Black people haven't had time to change. The reason they suddenly score so much higher on IQ tests is that society has changed, and the reason they still don't score on par with whites is that society still hasn't changed enough.