The idea is that a genetic theory of homosexuality makes no sense at all, since a genetic mutation that was so counter-productive to reproduction would be rapidly eliminated by natural selection. There are a few alternative explanations, such as that this deliterious mutation is linked to some other beneficial function (which explains the genetic survival of disorders like sickle-cell anemia). But Cochran's preferred explanation is non-genetic -- instead he hypothesizes that some infectious agent affects brain development.
I don't really have much of a stake in the politics of homosexuality. Cochran's science seems solid if speculative (and identified as such); his ideology is hidden although he has some associations to the rather suspect crew of Steve Sailer's Human Biodiversity Group. I find issues where science and politics intersect rather fascinating from an epistemolgical point of view. Presumably there is an objective fact-of-the matter about things like the origins of homosexuality, global warming, race/intelligence connections, etc. But it is almost impossible to investigate these issues objectively. Everyone involved, including scientists, seems to be quite agenda-driven. My personal strategy is to try to not associate with either side and find a neutral middle ground, but that is often difficult and unrewarding.
The name is somewhat biasing. If homosexuality is caused by an external organism, it is not necessarily pathogenic, at least from an individual's point of view. It is pathogenic from the standpoint of natural selection, because it reduces the rate of reproduction, but people do many things that are good for them but bad for their genes. So our hypothetical gay infection could be considered a symbiote rather than a pathogen. It is quite certain that a large percentage of the infected would prefer not to be "cured", and a different percentage would leap at the chance. In actuality, it is unlikely that there would be a cure since the action of this hypothetical pathogen probably takes place during early development. So no individual cures, but possibly parents could decide to take some inoculation that would be designed to knock the pathogen out of comission before they get pregnant.
Obviously those with a stake in homosexuality as a lifestyle or subculture get incensed at this prospect, and I can't say they are wrong to do so. Megan McArdle makes an analogy to the case of deaf culture, which is not happy that deaf children can be given cochlear implants and cured, removing them from the deaf culture and community. And deafness is much more clearly a pathology than homosexuality.
But I wonder if wiping out the homosexual pathogen/symbiote would be a calamity for humanity as a whole, let alone the gay subculture. It is unquestionably the case that homosexuals, like Jews, have made contributions to the mainstream culture far out of proportion to their numbers. You may not care for Broadway shows or the Village People, but
... there's no part of the cultural landscape without a gay element. Even if gays constitute as much as fifteen percent of the population, the gay contribution to Western art, architecture, music, and literature far exceeds what it should be statistically. If you accept the right-wing claim that only one in a hundred people is gay, then the gay contribution is truly extraordinary. Think about it: A group comprising one percent of the population producing Erasmus, da Vinci, Michelangelo, Caravaggio, Marlowe, Bacon, Hölderlin, Hans Christian Andersen, Tchaikovsky, Proust ... the list goes on and on to include three of the four major nineteenth-century American novelists, one (perhaps both) of the two great nineteenth-century American poets, and two of the three most noted mid-twentieth-century American dramatists.Not to mention Alan Turing, John Maynard Keynes, etc...
So, let's suppose the pathogen theory turns out to be true, and that medical research comes up with some sort of vaccine or other technique that interferes with it. The result could be that we plunge our culture into a dark age. Certainly we'd eliminate a lot of valuable diversity. The net benefit to humanity seems very likely to be negative.