To speak of AI models being "made public domain" is to presuppose that the AI models in question are covered by some branch of intellectual property. Has it been established whether AI models (even those trained on properly licensed content) even are covered by some branch of intellectual property in any particular jurisdiction(s)? Or maybe by "public domain" the author means that they should be required to publish the weights and also that they shouldn't get any trade secret protections related to those weights?

Are you threatening me with a good time?

First of all, whether these LLMs are "illegally trained" is still a matter before the courts. When an LLM is trained it doesn't literally copy the training data, so it's unclear whether copyright is even relevant.

Secondly, I don't think that making these models "public domain" would have the negative effects that people angry about AI think it would. When a company is running a closed model internally, like ChatGPT for example, the model is never available for download in the first place. It doesn't matter if it's public domain or not because you can't get a copy of it. When a company releases an open-weight model for public use, on the other hand, they usually encumber them with some sort of license that makes them harder for competitors to monetize or build on. Making those public-domain would greatly increase their utility. It might make future releases less likely, but in the meantime it'll greatly enhance AI development.