The law actually does a better job than you'd think. While it says little about stealing work to train neural networks, it does say that the final result requires significant human input to be eligible for copyright. It's the same precedent that prevents the copyright of a selfie taken by a monkey. Non human intelligences can't own stuff, and AI art isn't made by a human intelligence, so it's all public domain right now. It cannot be stolen unless someone has put in significantly more work on top of it.