I just don't understand people saying "but a human learning from a book isn't illegal".
How do people not understand that some laws only make sense at a certain scale? One human learning from resources and being added to the labour pool is not the same as an infinitely copyable entity doing the same thing. One has negligible impact on the demand for the original, and the other replaces 99% of the demand."
And creating a rule that says you cannot train on any material unless the rights holder authorises it via license is not complicated. That will creat a amrketplace where creators can decide the price for their content. It's just inconvenient.
I agree that there is not an orange to orange comparison, but I have still not seen a law that could scale as well. The example that comes to mind with a proposed law like this is how would you license work that build on another work? What if I decide to publish a blog post after taking some course, that distills whatever I learned in the course for free?