In free market capitalism there would be no black market. The sex INDUSTRY is a market to be capitalised in a free market, that being; pornography, sex tourism, prostitution, pimping, brothels, which is the manufacturing of sexual content, or supply a sexual service. You want this regulated; or banned, that is not capitalism, that is not free market, and that is not libertarian.
The black market as an ideology that is glorified by libertarians as it is an example of a market free from regulatory influences and control. You don't understand your own ideology, you don't understand those you critique, you are a fool that needs to read a book and not watch youtubers