Jamie Lynn Grumet, the 26-year-old mother featured on the cover of Time magazine breastfeeding her 3-year-old son, has done more this week than become the poster woman for “attachment parenting,” the sometimes laudable movement that advises parents to be physically and emotionally available and responsive to their children. She has shown the limits of such a concept, and the ways in which it can be twisted into a bizarre, contemptible caricature of itself. Grumet is a model, and models have to have at least healthy dose of narcissism (television journalists like me, too, by the way). But I fear Grumet...