And here comes my 2 cents (or maybe 10):
While I agree that men are the enablers of the whor phenomenon, I think a major theme of the book that a lot of us have overlooked is that within this thousand year old transaction, a man is looking to satisfy a baser need that he can't really control whereas a woman is looking to satisfy fantasy, greed, and other things that fall under wants.
A woman taking part in this transaction is looking to satisfy a less baser need. In fact they are looking to satisfy a luxury dreamed up in their days of playing with little dolls sitting inside of giant toy mansions.
Now, one could make the argument that the women's gain in the transaction is a natural need also (that of food, shelter, and protection). This argument would have held water if we were still living in 500-2,000 B.C. However, now feminism as well as a long list of laws favoring women over men in society has enabled them to take care of things like food, shelter, and protection for themselves. Their list of excuses for leeching off of men are running thin as time goes on.
The average modernized western woman is looking to satisfy greed, and justify this by boiling down sexual advances by man as "shallow", and other words that signify a compromise of conscience.
And if you think sex is not a human need, you are most likely brainwashed by your own beliefs and prejudices or simply ignorant.
Edit: I change my mind. Sex is not a need in the general sense (i.e. things required for survival). It is a need for the survival of our species, rather than that of individuals. Also, there are many who lead healthy lives without sex: people who are celibate or A-sexual. However it is needed to sustain a healthy relationship and psychological health. I don't think that anyone would agree that the same is true for money.
Society tries to tell us that we are different from other species. But we are just animals helplessly looking to carry on the legacy of nature and ensure our gene pool lives on. We just achieve it in an over-complicated way.
Maybe women use sex as a tool because they get the lesser part of the deal (i.e. possible pregnancy which in older times frequently led to death). I won't judge them for that, because I will never know what that's like. Men don't suffer nearly as much risk by engaging in sexual activity.
But just as I will never know what it's like to be pregnant, I don't think a woman will ever know what it's like to go through a day with a massive boner after seeing a mannequin in lingerie or a billboard advertising a strip club.
When it comes down to it, no matter what justifications the modern day woman will use for selling their bodies, they are still agents of greed. Men are simply trying to get their d1cks wet, because their hormones and psychic processes originating from instinct serve as a constant reminder of our most simplified reason for existence.