Hmm. I suspect they're being a little too narrowly focused.

The article says it's about polygamy, but even states that the dire scenarios are from sex-selected infanticide. (No mention of the roving gangs of unmarried Mormons in previous centuries.) It seems that the core problem is monogamous heterosexual expectations paired with an inequal gender ratio.

According to their hypothosis, it seems the more gay couples and the higher the divorce rate, the more stable the society would be.

Still, it's a great seed for a story idea!