Because public policy for fifty years has been based on the empirically incorrect premise that group IQs are NOT different. That false premise is why so many people assume that if the percentages of whites and blacks who are physicians or engineers are different, the explanation is racism. That's wrong. THE ONLY WAY TO PROVE THAT IS TO DISCUSS GROUP IQ METRICS.
I'm resorting to capitals because after 30 years I'm weary unto death of having to explain it over and over and over and over. Maybe the capitals will get it through the thick skulls of people who seem to be obsessed with not understanding it. I don't mean you, of course.