As a reasonably successful white male, let me explain:
It is quite obvious, if you bother to look, that the majority of black and hispanic students do not have as much access as us whites. They are more often from single-parent households or households where both parents work multiple jobs. They live in worse neighborhoods (because they can't afford anything else), and their older social peers are of worse character. Because of where they live, they attend worse schools. They may not have a computer or internet access at home.
The abject failure you see at the high-school level has its ground-work laid way, way back in elementary school, both in-school and at home. It takes a whole system to grind kids down and eliminate creativity, inquisitiveness, confidence, and a desire to succeed. Sure, some people will just meander through life and there's nothing you can do about them, but in my experience the majority of young kids have at least some area they show promise in and some level of curiosity. By the time they reach junior high-school, a greater percentage of black and hispanic kids have been put through the meat grinder and ruined. Further, since far more of their social peers are a result of the same failures, they spread an attitude of despair and pessimism about school and the potential for a better life. Just think back at the stupid crap you did when you were young as a result of peer pressure, now imagine everyone is peer-pressuring you to quit school because it's a waste of time.
This negative feedback loop continues to recycle people back into the same old situations and set them up for failure. Sure, some will overcome that and succeed, but it takes far more effort than it took for someone like me to succeed. Now we are just talking averages here, any individual case may be different. Chris Rock's kids live a life of luxury much greater than the vast majority of white children in the US, but that doesn't prove or disprove anything about the overall picture.
Similarly, I see people claiming that "some people are just going to be homeless", when actual experience shows that if you give homeless people an apartment free of charge first, then work with them to find a job, etc a far, far greater percentage of them do not go back to being homeless and end up as reasonable employed people who pay their own bills and are productive members of society. But that doesn't fit the story we like to tell ourselves that people "get what they deserve", so if they are homeless they must deserve it. Or the narrative that "some people are just losers/lazy/-insert adjective here- and there's nothing you can do about it."
Blacks from wealthy families in wealthy school districts exhibit the exact same test gap. Whatever the cause of "the gap" it isn't the schools or access to opportunity. We really need to stop wasting literally billions of dollars pretending otherwise.
