Dr. Kook lost me on this one. My guess is that viewers don't despise the performers. I suspect they are jealous of the performers.
But to think there are any health standards in the porn industry is like thinking there are any health standards in the illegal drug trade. When you fly below the radar of public morality, you should expect to be among dirty people. It's part of that rebel image.
If you were going to have some sort of regular testing or health registry, the first thing is these folks would have to give folks their real names. OOOPS! - That kills that idea.