I am sure that everyone in Utah felt disgust regarding the incident in which a 16-year-old girl was told, by her father, to enter into a marital relationship with an uncle.
The few eccentrics who have persisted in the practice of polygamy are in violation of the laws of the LDS Church and the law of the land.The folly of the practice is evident in the result. Inbreeding is a known cause of birth defects. And extremely large numbers of children give new meaning to the term dysfunctional family.
While some have made a case for a Dr. Strangelove scenario, i.e. an agrarian society faced with possible extinction (the situation facing Mormons in the 1800s), those conditions do not exist today.
The practice is unhealthy and should be discouraged insofar as is practical from a legal perspective.
Some have described these polygamist eccentrics as being "full of fervor." I suspect they are full of something else.