Money. That is why they get paid. We can debate how much and tell stories about porn stars who are stuck in bad contracts, but the systemic answer to exploitation is the exchange of money.
as
A slaver feeding their slaves is an answer to slavery.
Just because you get something in exchange, doesn't mean that there's no power imbalance, the exploitation doesn't exist, and the people with less power don't actually have few alternatives to survive.
If you're arguing for: "they should be paid more!" Because currently the pay is unfair and doesn't take into account potential long term damage, that's fair... But it's not a realistic solution (how do you unionize gig workers? Because at the end of the day, people on OF have more in common with the gig economy than with porn actors of yore)
The power asymmetry, physiological and emotional factors at play, the irreversibility of the action (the guys working you know that once they have a tape, you are quite easily manipulated), their gain and your potential damage exceed those in any legal industry.
Yeah, you are paid a hundred bucks and “money makes it legal”.
Here's the thing though, we do set a line after which you're legally given as much rope as you want to hang yourself with. I don't see how you fix the adverse outcomes without causing even worse failure in other areas.
Addendum: ah, and vastly different implications. Service in most countries is not associated with a stigma, is much more transparent, etc.