How does a person who isn’t black think about Black History Month? With respect? With reverence? With guilt? Curiosity? Indifference? It depends partly on that person’s own history—on when and how his family arrived in America. Those whose predecessors were present during the wickedness of slavery‚ and all that followed‚ will have a livelier sense of the black-and-white binaries of the story than immigrants lately arrived from‚ say‚ Kazakhstan. A white New Englander whose ancestors made a...