Homebrew, the answer has certainly been presented. It was described in the Kurtz quote I included in my first post (just little ways up), which instigated Apos’ seminal quote.
In an attempt to paraphrase it: Many American citizens are religious, specifically Christians. Many Christians (and other religious people) view homosexuality as immoral. For example, Catholic doctrine teaches that any sexual activity outside (heterosexual monogamous) marriage is “antithetical to a healthy, stable, traditional family.” For these individuals, they accept this premise on faith - it is not to be questioned.
I would presume that such individuals are concerned that homosexuality may “rub off” on their kids. They may be concerned that it will lead others to promiscuity or wild sex orgies. It may even lead to the decline of civilization as we know it. Or it may lead to cultural depravity the likes of which haven’t been seen since Sodom and Gomorrah (or at least Rome).
Now, I don’t believe any of that. But it is difficult to argue when people accept such a premise on faith. And it is difficult to not respect another’s deeply held religious beliefs (no matter how illogical). Even if you found someone here to debate with, I doubt you would find it productive.