Adult industry is digital content that can be "purchased" and then scraped before the chargeback goes through. Now the user has all the content that the site/model/whoever offers and didn't pay anything for it; they can then share it around, resell it, whatever.

It helps that a lot of people have no respect for the people producing the content; they'll happily consume it, but they refuse to acknowledge any work that goes into it or that people should be compensated for what they've created.