No its not the same selling your labor to selling sex. Because sex is something intimate. But your analogy is not wrong. When we sell our time doing something we dont like we also become prostitutes. There are things that should not be for sale, because they are holy. Time and intimacy are in that group. On the other hand making it illegal creates many problems and does not resolve anything. I personally think the real reason prostitution is illegal is so men are more willing to marry and to be under control of their wifes, years ago it was normal to go to a cantina with prostitues on it, and every respectable person was there. Back then the respect a man got from his wife was much much better also.