The reason is, "Admission to this specialized high school is based solely on the score obtained on the Specialized High Schools Admission Test (SHSAT). Students should speak to their school counselor in the Fall to register for the SHSAT. " (Source: https://insideschools.org/school/02M475.)

Rather than writing a piece that explains how the confluence of economic conditions, set largely in place by historical segregation and other racist policies, and the inadequacies of the primary school system together fail to consistently give black students the support they need to excel academically, and you can read out the failures in the entirely merit-based admissions rate to Stuyvesant, you make it into a story about intentionally not picking black kids because they're black ("When school administrators select only 1% of Black students to attend their best public schools, that is an active choice that administrators are making.").

Even though I agree that there are problems, the intellectual dishonesty (or egregious sloppiness at not learning the basics of your main example!) you display here is quite shocking.