Mormons used to (some still do) practice polygamy and we had just as much, if not more of a problem with their practices as we do with "foreigners".
From my perspective as another polyamorous person, I think polygamy is kinda fucked up, at least in the ways it manifests today. It's an inequitable power dynamic that relies on the exploitation of women. I'm all about subversion and defiance of hierarchies. Polygamy reinforces those hierarchies