The average person would then seem to have invested very little thought into what the word "unnatural" means i.e. the only thing which is unnatural in our reality is nothing as that seems to be the only thing that doesn't exist. If it can exist, then, like it or not, it is natural.
The problem with the natural argument is that the revulsion people feel instinctively for homosexuals is also natural. Of course, try to argue with a liberal that homophopbia is just something one is born with. Lulz are bound to ensue.
Desirable and undesirable, normal and abnormal, those seem to be the terms you are trying to communicate.
Natural != proper. But improper != unnatural. What this means is that homosexuality is a deviation of a divine principle, but its existence is divinely mandated as well, in the sense that all possibilities are inherent in manifestation, including deviations and degeneration, in that manifestation, being other then God, cannot be perfect. Yet, manifestation comes from God, and is thus an extension of
his nature, however corrupted this nature might become as manifestation grows distant from the source.
Homosexuality, as a deviation of a transcendental principle, falls right out of process of "consecrating" our fallen nature. To most people this may not mean much, including some of the most materially oriented Christians, who see nothing transcendental about life. But if you happen to be an individual with an instinct for transcendental values, and always made an effort to elevate things to an higher level, this business of certain individuals being "cursed" with a deviation which makes them unable to participate in any form of love and sexual union beyond its most vile and animalistic aspect, it is a very grave predicament to contemplate.
It would be easy to dismiss homosexuals as simply being evil, but that's obviously not the case which makes the problem very complicated.