Why the big flap over prostitution when sex is but a mere commodity anyhow?

With sex being reduced to a mere commodity why do society still have such a hang up about prostitution? People are hooking up all over the place and love and relationships are not obligatory. There are sites all over the Web for horny people to meet like minded people to get their Jones off and boink like bunnies, so what is the big deal, because someone is making money? Or that the perception is that none of those women love sex and figure why not get paid that we follow the standard boiler plate stereotype that they are all forced into the business, they were abused sexually as children, or they have to feed a habit?