Gay Marriage Causes Polygamy?

The radio and television news is pouncing on the massive child custody proceeding that began today in San Angelo, Texas, in regard to the children who were (at least temporarily) made wards of the state and taken from their parents, who lived in an unconventional local society dominated by a fundamentalist Mormon sect that encourages men to take multiple wives. (The shorthand for this arrangement is "polygamist sect.")

Addressing this case last week in the Washington Times, Peter Sprigg of the Family Research Council wrote:

The recent raid on the Texas compound of a religious sect that practices polygamy has raised again a number of issues regarding marriage, family, and sex. On the one hand, the existence of such a large group of practicing polygamists within our borders reinforces the concern that some have (which I share) that redefining marriage for the benefit of homosexuals would put us on a slippery slope toward other redefinitions-including legalization of polygamy.

Had I been drinking while reading this, my immediate reaction would have been a spit-take. (The colloquial abbreviation of the thought I had is "WTF?")

The group he describes aspires to live a 19th-century lifestyle, protect itself from secular influence by geographically separating itself from the larger society, and bases its rigid rules on fundamentalist religious beliefs. Yet Peter Sprigg wants us to think that this conservative sect's marital practices are the result of liberalized attitudes toward homosexuality and a robust public debate about whether gay men and lesbians should be able to wed legally.

Isn't this more than a bit disingenuous?

I think Sprigg is just being silly. He's so obsessed with the private lives of gay and lesbian couples that he thinks any unconventional living arrangements emerge only because of increased tolerance of homosexuals. Given that he uses gay marriage as a "hook" for his article on an entirely unrelated topic, his mode of thinking likely rests on the slogan, "If it's wrong, it must be gay."

If his absurd cause-and-effect argument were true, why aren't these weird fundamentalist compounds being built in Massachusetts or Vermont? Why do they pop up in places like rural Texas and Utah, where the animus against gay people (and opposition to same-sex marriage) is so pronounced?

Do people like Sprigg even ask these questions before jumping to unwarranted conclusions?