Because few social liberals would take the risk of coming out and saying “Black people in the US have lower IQ on average”, even though what it’s really saying

Because few social liberals would take the risk of coming out and saying “Black people in the US have lower IQ on average”, even though what it’s really saying is “Black people are often victims of a class divide, rooted in racism, that results in economic and everyday stress that causes lower intelligence”. It sounds racist to merely present the problem, going against the “all people are created equal” narrative because intelligence is viewed as innate, rather than something that can be developed (or harmed). So they fail to acknowledge the problem, which perpetuates the problem. ETA: Unless, of course, you come at it from another angle that doesn’t acknowledge the race issues but tries to solve the resulting problems—“schools need funding”, “kids need school lunches”, “careless gentrification is harmful”, &c.