By law, they monopolize up to half of a child's waking life for more than half of the year. This time commitment requires that parents put at least one meal, a substantial portion of the child's physical development, and almost all of their intellectual development (and, by extension, a substantial portion of their behavioral development) in the hands of the school.
If educational institutions are not taking seriously their potential influence on the social outcomes of their students, they're completely misunderstanding the practical mantle they've taken on. And so have you.