There are many polyamorous people out there who are not affiliated with Mormonism or any other organized religion.
Back in the 70's it was called "open marriage". But maybe that was about potentially involving a revolving door of short-term partners for each spouse (a la "wife-swapping").
The people who claim to be polyamorous these days need/want more than one intimate concurrent long-term relationship. They talk about having a "primary" and a "secondary" SO. It's all very open and accepted amongst the parties concerned, and it's not patriarchical. Often someone is married to their "primary". There is no polygamy involved (as in being married to more than one person).
To me, it's complicated enough having an intimate relationship with just one person!
I think a show about polyamorous people would be far more interesting than this one. Especially for the family dynamics and seeing how children are raised and whether the adults and children are emotionally healthy.
It's the hyprocrisy, I guess, that makes this show unbearable. What's good for the goose is good for the gander, as they say, IMO.