What would have possessed anyone to try it in the first place?
I'm not saying I'm going to run out and try kopi luwak coffee at the first opportunity (although its provenance doesn't particularly faze me), but to those wondering how this particular way of conditioning coffee beans was discovered I'd like to say that serendipity must have played a large role. There is a
very long list of foods and food (preparation) habits that are revolting to many, but that developed quite naturally. Most of this happened a very long time ago, but it's an ongoing process, and one many of us have experienced personally in one way or another.
The people that first tried new things may have done so because they had little choice and didn't want to discard scarce food unless it was clearly unsafe, or because they simply weren't aware of the risks they were taking by eating it or handling it in a particular way. These conditions still exist today. Over time, experience grew and added many foodstuffs and preparation know-how to the local kitchens, albeit that the way there was flanked by many victims of the trial and error variety. Again, nothing especially new.
A (non-exhaustive) list of 'questionable'
* foods includes various smelly and moldy cheeeses, fermented beverages of milk, malt, blood and other origins, 'tenderized' and 'pickled' meats and seafood, insects, fungi, all in various states of 'ripeness'. And did I mention cannibalism? Whatever the issue, let's not forget that there is a reason there is no arguing about taste: after al, we all are literally unique, even though we may be quick to relinquish that for 'the greater good'. And we all know the latter suffers from a distinct cultural inertia, as if to balance things out.
Food preparation methods developed equally haphazardly. Even to date several cultures feed their babies foods their mothers chew first. Heating food to make it more digestible and effective likely developed by accident: 'food' remnants partially burned after fires turned out to still be edible. Conversely, once cooking food becomes the norm, the consumption of raw items gains a negative connotation. The mere idea of sushi still shakes many to their cores.
Similarly, there are several plant seeds that require passage through animal digestive systems to sprout, and these include those of edible plants. Agricultural societies would eventually have picked upon this and searched for them, particularly if they were rare and prized. Kopi luwak may have an origin along these lines, but that's only a guess. Besides, 'processed' kopi luwak beans would gradually and automagically reappear by equally natural means, which reduce any residual yukkiness levels. Whatever the details, the general idea should be clear.
*)
Obviously, this assessment is rather culturally dependent. The greatest tension between food and 'yukkiness' may be present in the urbanized western world, where the physical distance between food growing/raising and its consumption is perhaps the largest anywhere.
