There is an all-black high school in a run-down area of Philadelphia that consistently fields one of the top high school chess teams in the United States. I'm sure the people in that school stopped making excuses for their students years ago.
Which school is that? Masterman? (Not sure of the spelling). If so, only the top students in the Philadelphia school system are admitted. That's why it does so well across the board. In fact, I married a former student. (Of course, he's not as smart as he thinks he is, and I hope he reads that, too. Just kidding).