I'm actually very familiar with the argument, I've just yet to come across anyone who can corroborate it with evidence. Thus far, the only thing that's made is an association with ritualistic practices of sex to appease other gods at the time and the prohibition of same-sex intercourse (at least for males). A mere correlation gets us nowhere though.
It seems you'll have to do more than that however. No one here I think doubts that a perceived problem for many of the writers of the Bible was that false-god worship existed and that many had cultish sex worship in this regard. But the problem is that you'd have to make the case that only homosexual sex was done to accomplish this -- otherwise why not make the rule general to apply to anyone who has sex to perform cultish, idolatrous worship? Was there no temple prostitute who engaged in heterosexual sex? The claim seems too speculative and more suggestive of those who are desperately trying to amerliorate their faith with their homosexuality.
There are many approaches to the Bible, and I never disputed that, but when it comes to the Law, usually it is the case that things are taken pretty straightforwardly. As to literalism, even the most liberal believers take at least some things literal. I always find it amusing when, say, I speak to a Catholic or an Episcopalian and they'll dismiss literal readings of Noah's Arc, the Tower of Babel, the talking serpent in the Garden, etc. as absurd approaches, but will accept an invisible carpenter manifesting temporarily in the flesh to perform magic tricks and die for the collective sins of his species, ascend bodily to heaven after an interval of three days and wait in heaven to eavesdrop upon, and occasionally answer, the prayers of millions of people, awaiting one day to return. If you allow for the possibility of literal readings some of the time, it begs the question as to what process is being used to determine which supernatural stories are true and which are simply metaphore and the like.
