The essay is a response to an essay by Brennan and Jaworski arguing that anything you can do for free you can do for money, ethically. Barber's argument falls apart when he simply assumes that it makes itself:
They demean goods such as human dignity by defending their sale, and then insist buying and selling cannot really demean those goods but rather ennobles the money with which they are purchased! “Hey babe, sell me your body! No, I’m not commodifying your body, I’m de-commodifying money! Money’s cool, and when I put a price on your ass I am paying it an enormous compliment!”
Now, the original argument that money is ennobled (if they are representing it accurately) may not be great, but the assumption that "selling" one's body (shouldn't it really be called "renting"?) not only commodifies it but that this in turn demeans it just cannot be assumed by using mocking tone. The fact is that prostitution has gone on forever in every culture, and it has at times not been considered demeaning, and in almost every culture and almost every time there have been one or more slight variations on prostitution - not called prostitution - which were not only not held to demean but were sometimes praised.
I am not merely talking about the concubine or similar roles, what I am referring to is the exchange of money for sex which is dressed up as "courtship" but which is just a hidden form of prostitution, in which the man pays (for the food, the whole evening, and also gifts) and if he gives her enough of this showering of money (maybe for a few nights not just one) then she gives him sex. Why is the man expected to pay and the woman to only give sex to men who are good enough to spend money on her? Because it is all a form of prostitution by another name.
And then the long-term form - the economic marriage - is even considered noble or even religious - but the man is still expected to pay a dowry, or to give her a diamond ring, or in some other way to give her money for sex (and - in turn - children, since it is long term). I am speaking not of love marriages, but those which are clearly about money and sex/childbirth. Consider the sayings: "give away the milk they won't buy the cow" (or "don't let them ride the rollercoaster without buying a ticket" - from Big Bang Theory).
Anyway, in many cultures today we consider outright prostitution to be hush-hush, naughty, even wrong. Among some sub-cultures the women are treated really poorly - it is sickening, both hypocritical (the men are forgiven, those who do it in hidden ways are all forgiven) and cruel, prostitutes are not even considered women, let alone human! But certainly not in all cultures- at least the French have a more reasonable attitude, so I hear.
Bringing this back to the article: is it money, commodification, that supposedly "demeans" or perverts the interaction in which money is exchanged for sex? Well, if it does, then all these other examples of money for sex would be demeaning (or perverse) too. And of course, arguably they are. But I don't think that they are seen that way. It is not about the money - women have long expected to be given money for sex. It is something else. It is the selfishness of the exchange maybe - which is why "casual sex" is often seen as demeaning too ("don't give away the milk for free - then he won't buy the cow" -- the money is the less demeaning bit, giving it away free is demeaning!) when it is assumed that the man wants it more than the woman.
This is why pornography is often seen as demeaning and/or perverse - the women are being "used" by the men (in heterosexual type naked female porn) who want only to gratify themselves. So, it's not about the money but about the selfishness. Now, consider the organs for money thing discussed in the articles -- and let's trade money out for another type of selfishness. How about sexual gratification: would it be demeaning or perverse if people gave away their kidneys not for money but because they found it sexually gratifying? Probably - it would be considered perverse.
But, as I said at the start, this is all cultural. And it's not obvious - the quote above is not an argument, and I expect better from Cato Unbound! :)