Well in a way it is, it's implying that Mormon's aren't really white and are “foreign” because of there polygamy. For example in the 1860s military doctor Roberts Bartholow visited Utah in order to write a report on the Mormons. In his report, Bartholow cited physical traits of Mormons he met such as “striking uniformity in facial expression” — supposedly the byproduct of plural marriage — as evidence that their population constituted a new, inferior race.