What I Know

Ok, so, in America, there are prostitutes. Not nearly as many as there are in other Countries, but, yeah, they're here. From what I know, prostitutes are illegal in every state in the US except Nevada. That means that the other 49 states dont approve of it. My question is "why?" Humans are sexual beings; people try to avoid talking about sex because it is seen as "taboo", but it's there and it's important to a great deal of society. So, my question is, if people are sexual, and these prostitutes are doing what they do out of choice: why is it illegal? In America, we have the freedom to choose. If a man or a woman feels that they want to, or even need to do it to make ends meat, don't they have the right to? In my opinion, a law is made for one of three reasons: to protect the person breaking the law, to protect people from whomever is breaking a law, or to keep America moving smoothly with necessary actions or perameters, such as taxation. If i am correct in my classification of laws, under which of these lables does prostitution fall? Honestly, none of these. If one feels that buying a prostitute will make them happy, and the prostitute is of this profession willingly, then how is prostitution such a evil, and destructive profession?