Eminem Is RightBy Mary Eberstadt f there is one subject on which the parents of America passionately agree, it is that contemporary adolescent popular music, especially the subgenres of heavy metal and hip-hop/rap, is uniquely degraded — and degrading — by the standards of previous generations. At first blush this seems slightly ironic. After all, most of today’s baby-boom parents were themselves molded by rock and roll, bumping and grinding their way through adolescence and adulthood with legendary abandon. Even so, the parents are correct: Much of today’s music is darker and coarser than yesterday’s rock. Misogyny, violence, suicide, sexual...