The people generating it are rarely the ones who are training the models. They take pretrained models and prompt them for what they want.
Even if they were training a model for a specific subject, they could train it with any pictures of the subject and combine it with another model that can generate the kind of image they want.
There is absolutely no reason they would need abuse images to use for training. There are far better general nsfw models available right now than they could ever train themselves.
I accidentally used this loophole with Starfield.
Wrote a whole thing pleading my case thinking there might be a slim chance of it getting approved since I was considerably over the 2 hour limit. But it ended up just getting auto approved within an hour or two.
I was initially shocked, but quickly realized what happened.