I'd say that your comparison to prostitution is invalid because simply having sex doesn't hurt anyone. Sure, it has the potential, but there are some prostitutes out there who are in that business because they like to have sex, in the same way that I'm a systems administrator because I like to work with computers. Certainly, there are many women out there who have sex with other men for free; why not get paid for it? On the other hand, there are as many people who work on computers simply because they thought it was a good career path, and, I'm sure, there are some prostitutes that thought the same thing. (There's some debate in my head as to which of those two groups was the least wrong. ) And there are virtually no physical maladies in those areas where prostitution is legal (in the U.S., at least -- I won't speak of Thailand, Brazil, etc.), as government controls keep much better care of them than any (okay, most) pimps would. (Madams may be a different story.)

Not that I don't understand your point.