It’s important to understand the political climate before the NY State legislature decided to pass Hecht-Calandra in 1971. The New York Times does a great job filing in that context.

In 2016, a proposal to send some Upper West Side children — who were zoned for a high-performing, mostly white, wealthy elementary school near their homes — to a lower-performing school, attended mostly by low-income black and Hispanic students, about a ten-minute walk away, was met with vitriol.

A version of the plan — which ultimately impacted a relatively small number of schools — eventually passed after years of negotiations.
B犀利士 ut the recent push for integration has been led in part by liberal white parents.

Some of these parents helped force the most comprehensive local desegregation policy yet: the elimination of screened middle schools in Brooklyn’s District 15, which includes upper-middle-class neighborhoods like Park Slope. Some parents there have said the election of President Trump prompted them to combat segregation in their children’s schools.

https://www.nytimes.com/2019/03/26/nyregion/school-segregation-new-york.html