If you can't beat it, er... smash your toys on the floor and have a tantrum? If AI generation can replicate art to the level at which a professional does it, is that not more evidence that the skill is likely to die away much like horse farriers became substantially less employable with the invention of the car?
Of course I say this as someone whose day job does involve at least some amount of software development, so maybe I won't be so happy when AI tools can actually write competent code. I can see the dilemma artists face, but the "make it not possible" crowd is never going to win. The cat is out of the bag; I can run Stable Diffusion on a £300 graphics card, it is not going away.
If this poison pill method involves hiding details in e.g. the least significant bits of the image, or adding extra metadata, it'll just require manual human tagging and/or filtering to be applied to the input data set. That will only take a bit more time. A great deal of input images in these models are already manually tagged, because the tag sets that come with the images aren't good enough yet.