First of all, I'm not "demanding" anything. I asked for examples of "societal shaming/labeling" that many- including the OP- seem to indicate are so common. I asked for these because of the claims don't seem to match reality.
As for societal disapproval... you're partly right. Society is, however, the collective consensus of the majority. The stories of friends & family shunning are completely irrelevant to "society". Anecdotal evidence & society don't even belong in the same sentence as one another.
And this comes right back to my point that, until open polyamory is as common as, say, openly belonging to some other sort of a minority, you won't get the sort of institutionalized discrimination against it that is the question of the thread.
When being gay was a dirty secret and not an openly lived identity for many people, you could say, "there is no discrimination"...sure, a majority had their opinions, but since they didn't have brave targets walking around to sling real life consequences at, it wasn't a big deal, right?
But as homosexuality became more of a public reality, the questions arose such as whether it is a thing you are born, or a thing you choose. I imagine that many who asked those things, with an eye towards fixing what they saw to be an aberration, either through some kind of reprogramming like these abominable conversion camps, or through maybe medical treatment or genetic therapy if indeed it is biological... Ah, but in time, many, especially in more progressive areas, have come to decide that there is nothing wrong to be fixed. And I do think that shifts in "majority" thinking (as compared, say, to the mindsets of the 1950s or prior) will help other groups such as the polyamorous, be treated fairly. If most people believe that your love life is your own business and has no bearing on other aspects of how you should be treated, well, that is all to the good, right? But there are still plenty of right wing pundits out there aghast that "consenting adults" is the standard. Who would pontificate to the masses that this is not a godly way, that marriage is between ONE man and ONE woman, and anything other than that is against God, nature and all that is good.
And so it becomes a matter of politics.
And if ever polyamorists come "out" en masse, as gay people have fought to do, and threaten the safe little worldviews of the narrow minded, by demanding to be acknowledged as living valid lives, then I expect there will be a certain amount of possible backlash, and some politics will start to flare up about it. People will talk more about whether it is "born that way" or a choice, as though that even matters. The more progressive will shrug and ask, "who cares?"
Until this administration, I honestly thought that the United States was happily marching towards more socially liberal attitudes, with gay marriage being more widely accepted, and the pot laws being relaxed...a more general state of freedom for people to choose their paths, so long as they aren't harming others. That these mindsets were gaining ground. But it's not just the great orange arse that concerns me, our entire government is now dominated by the right.
I guess it is worthwhile to ask... Let us use the gay comparison here, if you are a gay man in a rural Bible Belt town, and you don't dare come out because you know how people talk, and you know how violently they can react to things they don't approve of, and you'd rather not be beaten or killed...or let us say you would be transgendered, if only you did not live in a place where just a few months ago they murdered the last person who contemplated transitioning... If you choose to not put your life in danger, and so hide or suppress yourself deep into a closet in order to be safe...
Does that mean that there is no discrimination?
Does a troll exist on the internet even if you don't feed him?
And again full circle, I would argue that there are some dangers that a reasonable person can intuit about the world around them, without necessarily having seen the reality come full to fruit. I have never seen a train run over a human being before, but I still won't fool around on the tracks.
If you're in a place where you look around you, and the people you know are fairly intelligent, openminded folk, who don't mind others being different so long as they aren't being harmed or affected, and who would likely be fine with a poly family living next door, then COUNT YOURSELF LUCKY. Because there are still plenty of places in the US where that just is not the case. I have seen enough discrimination and ignorance aimed at plenty of other kinds of diverse people who happened to not be cis-het-whitebread-normalsauce in some way, that I don't really feel a need for statistical proof. And what you think of, when you hear "society" is gonna have a lot to do with what flavor of society is walking around in your immediate environment. If you think that the residents of middle-of-nowhere Arkansas, or Missouri, or Kentucky are going to be as accepting and non-discriminatory as the population of California, or more to the the point, the Pacific Northwest for instance, you will be sorely mistaken.