Mormons and some Muslims practice polygamy not polyamory. I talked about the difference in the story. Did you even read it?
Polygamy is not good for women but polyamory is very, very good for them because as I already said - repeatedly - in the story, it encourages people to be non-controlling, responsible for their own emotions, honest, and communicating well. This is much better for women than the patriarchal dyanamic that is still in most monogamous relationships.
"Polygamy is the practice or custom of having more than one wife or husband, although in nearly all cases, polygamy has historically been a patriarchal structure where the man has more power in the relationship, and the wives are subservient and dependent on him.
Polyamory is the practice of engaging in intimate relationships with more than one partner. There are no inherent rules or roles because every polyamorous relationship is defined by the people who are in it to suit their own needs."
I also clearly said this: “It is theoretically possible that a man might have 30 partners, but they would all be free to have their own additional partners as well and most of them would probably have multiple partners.” That’s very obviously not the same sort of relationship structure practiced by radical Mormons or Muslims.
There are all sorts of cultures around the world that don't practice strict sexual monogamy and it works quite well. You are letting your biases cloud your ability to perceive things that have been made very clear.