Will things probably be OK? Sure. Probably. But GNU is particularly risk averse when it comes to licensing.
I am however very interested in the novel interpretation of copyright that says that you can do whatever as long as your compression is lossy.
If you imagine it as a "box" you feed into it material and a prompt and it spits out the same material rearranged to do what you did ask for. It does nothing more than a permutation of their input data, as does any computer program, of course in extremely complex and obscure way, but if you reason it abstractly it's the same things Turing theorized almost a century years ago, input -> BOX -> output.
So *of course* the output *is* a derived work of the input, and thus a GPL code should not really used as a training set.
Here's a very basic example: if you have access to a typical language model's weights, you can subtract the embedding for "man" from the embedding for "king", add the embedding for "woman", and land somewhere very close to the embedding for "queen".
Why is "intelligence", whatever that means, a prerequisite for a machine to process ideas in the abstract?