IMO, prostitution can be broken down into two groups. Those that do it because they feel empowered and comfortable enough to know that they are selling their time and not their souls, and those who do it because they feel they have no choice. I'll not talk about the former, because I can't see what the problem with it is.
The latter, however, is a problem. Again, I don't have a problem with the institution of prostitution per se, but rather why women and men feel they have to do it. I'm no expert in this area, but it seems to me that the vast majority of those who meet this description come from homes where they were molested, abused, neglected, or otherwise dealt a horrible hand in life. Many of these same people who turn to prostitution or get put into situations where they are forced to become prostitutes also seem to do it to pay for drug habits that I imagine developed directly or indirectly from what they experienced at home.
Demonizing these prostitutes isn't helping them or those that will eventually take their place. Making prostitution illegal only tackles the symptoms of a disease, not the disease itself. It wouldn't be easy, but fixing the reasons why many prostitutes feel they need to sell themselves (or get into situations where they have themselves sold) would do a whole lot more good than arresting them.