Typically polygamy has been asymmetrical and part of an undeniable patriarchal power structure (one man, as many wives as he can afford).
But if we're talking about symmetrical polygamy (multiple husband's and multiple wives), I see no reason why a modern secular society should care. Of course if everyone is married to everyone, is anyone married to anyone?
I vaguely recall a species in startrek that was like this.
Agreed that some religions use marriage as a power structure, poly or not - but that was the case even for many secular monogamous marriages in the US until relatively recently. Marital rape is legal on the books of many states!
There was a poly society in season 1 of TNG. I think it was episode 2 or something like that?
It is the episode where Natasha has to fight another woman for her life.
But if we're talking about symmetrical polygamy (multiple husband's and multiple wives), I see no reason why a modern secular society should care. Of course if everyone is married to everyone, is anyone married to anyone?
I vaguely recall a species in startrek that was like this.