There are plenty of reasons, some material and others not. They are obvious and very expressible. But, again, I will not honor the Randist-style (inadvertant or not) blinders you place upon the question. I do not accept your wilfully ignorant conditions. I won't play your silly game.
End of transmission.
. . . because you can't. So instead, you bluster up in an effort to dismiss and deflect.
However, from where I sit, the effect is the same. If there were a rational argument for prostitution's illegality---one that wasn't based on religion---you would have made it by now.