I think what he is saying is chinuch involves several partners (school and parents at the basic level) and while the school can teach something until they are blue in the face, if it is not reinforced at home, or worse a contradictory message is given at home, then it is a partnership doomed to failure. He seems to acknowledge that mothers should of course be reinforcing the message taught in school, but since they are not (can not?), fathers/husbands who also have a responsibility for the kedusha of the home, in fact the primary role, (and as it relates to their daughters, an obligation of chinuch) need to step up to the plate. He wonders why they are not.
