there is only one way they survive on those sites. the Dev. pays for the stock image or vids to use in their game. If they don't do that then they get banned and sued (if they made enough money to be worth the legal battle). Most porn actors have copy rights on their body's and their vids / images. Ever vid or pic you see that was taken has a legal contract involved and that is how they keep it legal. Other wise they would be just street walkers selling themself on the corner and that is illegal.
Now if you make a game that is free and you use them you might have a loophole and getaway with it, but for the most part if you want to make money form them then you will have to pay them or the contract holder for the vid or pic you want to use.
Actually, actors and actresses generally have the right to their images, often referred to as "rights of publicity." However, the copyright of the movie itself is typically established in a contract and usually belongs to the studio. This means the studio can often use the video footage they own in compilations without additional payment to the actors, beyond their initial compensation.
In the case of self-produced movies, the copyright usually belongs to the owner of the channel or production company, unless there's a contract stating otherwise. This is often the actor or actress themselves.
If someone uses stills or video excerpts from a movie illegally, both the actors and the studio can sue. Actors can sue for the unauthorized use of their images, while studios can sue for copyright infringement. In the case of self-produced videos, the owner can sue for both copyright infringement and the unauthorized use of their images.
It's important to note that, there's no loophole: even if the use of the material is free, it's still considered infringement. However, the severity of the consequences can vary. In some cases, the infringer may be ordered to pay damages, while in others, a simple "cease and desist" letter may be sufficient. The court may consider factors such as the infringer's profit and the likelihood of future infringement when determining appropriate remedies.
Anyway, I was more concerned about how Patreon handles its policy. Even if a developer does everything by the book (which I think is rarely the case), as far as I know, Patreon forbids porn with real people in all circumstances. Therefore, I conclude that Patreon doesn't strictly enforce its policy until someone complains or reports it.