IN YEARS to come, it seems very likely that historians will shake their heads in disbelief over many of the events that occurred between 1960 and 1975. Among the things which will dismay them is the fact that during the era when Americans became concerned to the point of obsession about minority groups—Puerto Ricans, Chicanos, blacks, American Indians, Appalachian whites, homosexuals, prisoners, old people—there was virtually no interest shown in our largest minority group, Roman Catholics.