why is prostitution considered 'wrong' ?

A question that has been on my mind for a long time was put in by my friend Mary (he is the sysadmin at Sarai). Let me give a bit of the background. When I was in Delhi, a bunch of us fellow-geeks used to meet almost twice a month to talk about our hacking projects, our current work (all of us were happily free of NDAs), have a good dinner and generally get into debates about topics that would be considered a taboo (or inappropriate by most people). Once when we were joking about how prostitution is legal in Thailand and what procedure would the government be using to collect the taxes (I mean, how will they cross check the receipts), that Mary popped the question "Why do you think prostitution is wrong ?" . My first reaction was "It is not the right thing to do" - however, I realized that pushing my judgement of what is right and what is wrong on someone else is not the correct thing to do. I have been thinking of why I consider prostitution to be wrong - it is a profession - a service is provided and a price is paid for it.

This question again came to the front of my mind when I read this blog post by Joshua Newton. He writes about the An autobiography of a sex worker by Nalini Jameela. He posts the following quote from the book

Some see brothels as a space for sexual perverts.
They are wrong. Why do people of all walks of life come to us? Parents prevent our sexual desires in the beginning. Then teachers in schools. Then moralists in churches, mosques, and temples slap rules. When you grow up, police and courts take up the role. They spread the rule one man for one woman. Yet people seek out prostitutes all over the world in all ages. What does it prove?

So are you against moral structures?
No. Men dictate the morality of this age. They use wives or sex workers to their ends. We dream of a new dawn of morality. Sexuality like food and shelter is a terrain of human tastes. It is still to be developed into a plateau of endless tastes and forms. Morality should not suppress. It should be liberating. When sex work turns into one among many human service sectors, you will stop suppressing yourself and others.

I have not read the book but this book is definitely on my to-read book