The point of Job was much more dramatic that an invitation to patient suffering. It challenged the fundamental underlying assumption of Hebrew society that the faithful prosper and the bad do not. That assumption is grounded in the fact those Hebrews did not the notion of a heaven versus hell, for their Sheol was the single post-death place of repose for all, and Sheol was less desirable than this life. It was not until the very last layers of the OT that the notion of a positive life beyond the grave emerged. 
Divested of that notion of punishment (which I do suggest is very much implicit in your prior comments), I do agree with you that we have to learn from nature. The way you are not putting it, you are, it seems to me, postulating the foundation for the notion of natural law. And based on that law, homosexual and heterosexual behaviour are equally natural; and both suffer STDs. And, yes, as you say promiscuity plays a role. Ego, monogamy, gay and straight, is a good thing.