I guess it's a chicken or the egg scenario but I tend to think the Inchoroi's proclivities preceded (and caused) their damnation. It comes back to them being a very technologically advanced society for two reasons:
1) I read an interview where Bakker was asked about the Inchoroi and he only vaguely answered by pointing out how division of labor gives people more time to pursue their interests or pleasures. Given how advanced they are, they've likely had plenty of time to refine their adoration of the flesh.
2) this is Bakker's universe and he is of the opinion that scientific understanding necessarily displaces our notions of cosmic significance. On such a teleological timeline, their scientific sophistication suggests they probably had a very nihilistic view about themselves and the universe. It's easy to see how such a race would be inclined towards hedonism, without any fear of an afterlife, karma, or any format of idealism for that matter.
So they were free of conscious and obligations to go to pursue their carnal pleasure, only to discover (or accidentally misinterpret) that damnation is actually real. I suspect Bakker is positioning the Inchoroi as what we may easily become, and alot sooner than you might think. As we recognize the arbitrary nature of our traditional sexual prohibitions and further develop our ability to physically modify ourselves, it's not to far fetched that we would be rocking clam heads with wings and pheromone releases