This is OK and fair use: Training LLMs on copyrighted work, since it's transformative.
This is not OK and not fair use: pirating data, or creating a big repository of pirated data that isn't necessarily for AI training.
Overall seems like a pretty reasonable ruling?
I tend to think copyright should be extremely limited compared to what it is now, but to me the logic of this ruling is illogical other than "it's ok for a corporation to use lots of works without permission but not for an individual to use a single work without permission." Maybe if they suddenly loosened copyright enforcement for everyone I might feel differently.
"Kill one man, and you are a murderer. Kill millions of men, and you are a conqueror." (An admittedly hyperbolic comparison, but similar idea.)
That's not what the ruling says.
It says that training a generative AI system not designed primarily as a direct replacement for a work on one or more works is fair use, and that print-to-digital destructive scanning for storage and searchability is fair use.
These are both independent of whether one person or a giant company or something in between is doing it, and independent of the number of works involved (there's maybe a weak practical relationship to the number of works involved, since a gen AI tool that is trained on exactly one work is probably somewhat less likely to have a real use beyond a replacement for that work.)