Yes, Viliam made an extremely poor example. No, this doesn't affect his main point, because he could have made a better example instead. Sweatshops do exist and yet AFAIK nobody's ever proposed to ban selling clothes for money.
Prostitution has an unusual feature: for a given level of need for money, the ratio of "how much would most people who have X have to get paid in order to be willing to sell X" to "how much money would X get if sold on the market" is extremely large, compared to a similar ratio for, say, selling one's labor as a janitor. The dynamics of things with large ratios of this type lead to slavery and mistreatment much more often than the dynamics of things with smaller ratios of this type.
That doesn't mean that people in other jobs can't be mistreated; obviously, sweatshops do exist. But it does mean that mistreatment is less central for those other jobs, and is less relevant to banning them.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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