Especially frustrating was the fact that de Blasio, flaunting his bona fides as the city’s first public-school-parent mayor, was turning away from a program, initiated by Mayor Mike Bloomberg, that had delivered real dividends for kids, albeit while earning the ire of organized labor. Namely: more swiftly closing schools, reconstituting their staffs and creating small schools with healthier climates for learning, while letting as many high-performing charter schools as possible bloom.