The creators of the play Book of Mormon have created the Amos and Andy for the South Park set. We may laugh, but our grandchildren will shudder as decent folk do at “wits” of the last century whose favorite dance was to “jump Jim Crow.” The parts of the Book of Mormon I have seen are as innovative as a Newsies revival and as funny as the cruel, tasteless jokes told by an inebriated coworker at a Christmas party. The difference is that the coworker might sober up in the morning, but the mindless mockery that also gave us South...