Could you help me to correct my article which is about the legislation of prostitution in China?

I don't know why people always judge things with dichotomy: It's black or not. A fair bit of things have existed since the society of human beings formed. Just like the line I have ever read in a GU LONG's fiction ( I forget its name) : The whore and the killer are two of the oldest occupations in the world. I consider them as a kind of instinct. It's spontaneous.
So, I don't agree with the viewpoint that prostitution is illegal, let alone legislation to forbid it.
First of all, prostitution is a contract between two majors. The adults have the right to dominate their body.Thus the compromise that has been struck for intrinsic requirement should be protected without the interference from the third party.
Then, I'd like to refer to a word "externality", spring from a conception of economics. For instance, forcing someone to be engage in prostitution or seducing someone to take part in an immoral transaction. In this kind of situation Government should forbid such behavior that is in what I describe as unwilling deal to prevent from the geniture of "externality". France is a good case in such aspect. (One of my friends told me that I should not use "case" because France is a "country". I mean that it's a good example. So what's the correct expression?) Prostitution is legal, but compelling or instigation is illegal.
Thirdly, prostitution should be lawful if its social benefit is better than the social cost in a perspective from law economics. The legislation of prostitution can improve the revenue and efficient administration, especially control the spread of venereal disease.
Ultimately, however, inhibition of the prostitution is a typical model that legislates according to the voice of masses. Is it right yet? I think the biggest problem is whether the so-called public moral order exists objectively or not. The moral rules and consensus change with the time changes.In short, I think moral is just for behaving self rather than others.
All in all, I figure that we have enough reasons to legalize prostitution.