Of course they’re prostitutes.
A prostitute is paid to provide sex for money. The performers in porn films are paid to provide sex. They are therefore prostitutes.
The customers are the ones paying to get sex. The producers are pimps.
No different from somebody in a mink coat and big hat who steers men to his stable, and skims the fees. The women are being paid to provide sex, the customer is paying to receive it, and the pimp arranges the transaction.
No idea how they get away with it legally, but “by behavior”, it is prostitution.
Regards,
Shodan