You'e exactly right, annalex. It was a decayed heterosexual society that broke down the "definition of marriage" so that it was temporary, serial, and sterile. At that point, it was exactly what gays were looking for: the gratification of adults, with all else being optional.
In particular: contracepting couples have already turned sex into an infertile-by-design, "unnatural act." They are heterosexual gays.
Good term.