It's in the flame board because it's idiotic, if it were a post posing "Why is prostitution illegal while pornography is not?" and offered some intelligent thought, it could have stayed.
As for the original post, if the camera is hidden, you're not paying her for appearing in a porn video, you're paying her for sex. As for why one is legal and the other not, that's not an opinion question but a factual one, which a little research would have lead you to
California v. Freeman - Wikipedia, the free encyclopedia
And @Meekins, am I to assume you don't like wikipedia as a source because you doubt its accuracy? If so you know little about its procedures, which ensure everything without a source to prove it will be either marked as such in the short term, and removed in the long term. Most of the bad press on Wikipedia is due to the often publicized vandals that get off on saying Samuel Adams is a character in Halo. 99% of the time it is obvious to a reader and in most cases won't last a day. The few remaining instances can be checked by looking at the talk pages and change listings to see anything recently added. Anyone who calls Wikipedia less accurate than a traditional encyclopedia must logically believe Linux is less secure than Windows because anyone could go in and modify linux to have a security bug! Except that open source software, like wikipedia has protections and peer review, sure something minor like a bug that crashes the kernel if they have 29 IBM mice from 1987 plugged in will happen (akin to Sam Adams), but they are always obvious and can be fixed by reporting the error and just looking at/using an earlier version