I'm for legalising it, albeit significantly less enthusiastically than I was when I first joined the forum. I am mildly disappointed that gays want to sell out by endorsing a concept like marriage, and irritated that it's literally the only issue that anyone seems to care about despite it being such a minor little thing that affects very few people.
'Cuz why not?
Anyway, I support Gay Marriage 100%, and it should be legalized statewide, I'm surprised it's taken the US this long to finally start to support it.
I don't know why you'd be surprised, the US has rapidly adopted gay marriage at a faster pace than most similar countries.
Polygamy is a whole different ball game to gay marriage, though. Polygamous societies are predominantly polygynous, so it degrades women and locks many men outside of relationships. Obviously piles of sexually dissatisfied men is bad news for society (don't laugh I'm serious), so I'm suspicious of promoting polygamy.
Given the way gay marriage has been promoted for the past 10+ years, I doubt people will consider those arguments valid. If I were to make an anti gay marriage post on Atlas or Facebook, one of the first replies would be something like "but they love each other, they should be able to get married".
A culture that bases its acceptance of gay marriage on "marriage=love" will have to accept polygamy too. Granted, there will still be inertia but it wouldn't be that surprising if our kids' or grandkids' generation feels the same way about polygamy that millennials do about gay marriage.
I actually think you're correct here in that acceptance of gay marriage will probably lead to polygamy becoming the next safe social liberal cause celebre a few decades down the road, but I don't accept the premise that that's inherently a negative thing.