A product is not a human. They are selling a product based off copy-righted material without the rights to it. It's a pretty easy line to draw, honestly.
A human who trains their brain on material they don't own then creates art or writes code based on this training, sells the product too.
(Not a lawyer, just a nerd)
The contention is obvious in your statement. Is it illegal to train a model, and why? Why is it legal to train a human on copyright material and then sell those skills, vs training a computer and selling the skills?
This isn't black and white.