QOD: On "Union Claim" that Charter Schools "Counsel Out" Special Needs Kids

A teacher from Eva Moscowitz’s Success Academy Charter Schools writes that anti-charter skepticism of student achievement reflects prejudice, and also refutes  allegations that the schools “cream” students for selection:
Success Academy critics, however, have a hard time accepting our students' academic achievements, even after a five-year track record ranking among the state's top-performing schools. Critics, among them the teachers union, claim we "counsel out" special needs or low-performing students to keep scores high. Success Academy loses fewer of its students (10%, including special needs students) each year than our peer co-located public schools do (21%). Despite evidence to the contrary, this myth is frequently cited as fact in print and online. Last year, 1,538 Success Academy students took the state exams; 13% of them were special-needs kids. Of that group alone, 56% of them passed math. An average of 7% of New York City district special-needs students passed math.
The newest theory regarding our test scores is the most outlandish. Jonathan Westin, executive director of New York Communities for Change, a union-funded nonprofit, was quoted in Bloomberg News saying that Success Academy is "trying to find ways to increase test scores; that's why they go into the wealthier neighborhoods."

Really? Is it just me—or does anyone else hear the prejudicial undertone in that statement? Is it really impossible for Mr. Westin to believe that Success Academy's poor black and Latino children can achieve at extraordinarily high levels? That with hard work and dedication, significant numbers of children in Harlem and the South Bronx and Bed-Stuy can be proficient at math and reading?