Given your comments about the interpretation offered by the Church Fathers, I had a quick scamper through John Chrysostom's commentary on the passage.

See http://www.ccel.org/ccel/schaff/npnf111.txt

Not my idea of fun reading - interestingly there he points to the 'giving up' suggesting that it is people who have access to straight sex who go on to indulge in gay sex, rather than pointing at those without it, as suggested by your emphasis on pattern of Morocco. I'd be interested to read more on what the Fathers say on the issue; does anyone know of a study of those writings?

I think an element you don't discuss is the degree to which gay sex is 'inherently unnatural' - not because it is or is not natural to the person, but because it is in accordance with the natural order; the 'Adam and Eve' not 'Adam and Steve' argument that God gave a woman to Adam to complement him, not another man. It's in that context that the whole thing makes sense to me - and leads to the logic that being gay is a form of disability; we are disabled from being able to as easily enjoy straight sex as the straight person, and are less fulfilled by it. To me this fits all the bits together ( ;) - sorry ) better, reflecting the experience of some who have turned away from gay sex as a part of becoming Christians without human prompting.