well, and my experience is that of the producers in the gay adult industry that *do* provide any testing at all, most (with a few exceptions) only test for HIV, and pay no attention to hep-C, which is equally incurable and can actually be harder to treat, and syphillis, which can also be really difficult to treat if not caught early?

I think, as Tony implied, the answer is ignorance. In some cases, I think the producers really have no clue as to the safety issues, and aren't really interested in hearing about them, because they themselves do some of these things and don't want to think about the risks.