My personal opinion is that it's unethical (and possibly illegal, in a subset of cases) to train models on data without explicit consent of the creators of that data. And that really encompasses all data - generative models were not a thing when said data was created and no matter how it was licensed before, explicit consent about using it for model training must be obtained from the creators themselves.

That being said, arguments about copyright are just a fig leaf as far as I am concerned. The outcome of whether this is allowed or not will depend on the net impact of using those models on the job market and whether society will be willing to tolerate it.