Perplexed by polygamy
The latest example of this comes in response to a poll claiming that 22% of people in the US think there is no legal grounds for banning polygamy, and 18% who see no moral grounds. The poll was reported first by the anti-gay World Net Daily. WND's headline asked "Why are so many cool with polygamy," but the article never even attempted to answer that question. The closest WND comes to explaining an anti-polygamy rationale is to simply label it a form of "barbarism," and quote California Justice Marvin Baxter's claim that monogamy is "ancient and deeprooted."
Note that these two claims are contradictory. One is an appeal to modernity, arguing that polygamy is a thing of the past and that we should be happy to have moved beyond a practice characteristic of an older form of society. The other is an appeal to tradition, saying that we should try to conform our laws to those of older forms of society. Whatever its normative merits, the "barbarism" claim is at least a bit closer to historical facts (though history is of course far more complicated), as the WND editors could confirm by consulting their own Bibles.
Gay news site EDGE then reported on WND's report of the poll. The EDGE story gave even less information about why anyone might support or oppose polygamy, preferring instead to simply imply that there was something nefarious about WND and the pollster making slippery slope claims.
On the other hand, as of this writing the two comments on the EDGE story both express a lack of concern about polygamy. (This is in contrast to the apocalyptic tone of many WND commenters.) For now, as reflected in the EDGE article, it remains the unofficial talking point of mainstream SSM advocacy to denounce polygamy and deny the possibility of any marriage-redefining slippery slope. But I would not be surprised if, in coming years, the common response to warnings about polygamy morphs into "so what?" After all, modern egalitarian polyamory -- of the sort practiced by not a few members of the LGBT community -- has a lot more in common with modern egalitarian two-partner marriage (between people of whatever genders) than either of them does with the hierarchical gender role differences characteristic of both traditional monogamy and FLDS-style polygamy.