Why would you expect them to do better after centuries of being taught to obey
The insinuation that a reason blacks don't do better because they are trained or bred to be obedient is pretty gross, and not that different from the racist "docile negro" rhetoric of a century ago. Why not start with expectations that anyone can better themselves, regardless of race? If you want someone to move up, do you think they have a better chance of doing it if society tells them the can, or they can't?