The N.A.A.C.P. had joined with the union in the suit, which among its other claims, said that the city had discriminated against traditional district schools by giving privately-managed charters a priviledged position inside the "shared" buildings including more time in common spaces like auditoriums and gymnasiums than the traditional schools. In other words, neighborhood kids and teachers were made to feel like second-class citizens in their own schools.
From the Brooklyn Eagle:
The multiple school closings have been characterized by some parents as an unfair rush to clear out under-resourced standard public schools in order to give their real-estate to charter schools backed by donors with deep pockets.