Training from copies has been ruled fair use because it's "transformative" and not simply "derivative."
This is obviously debatable, but that's where the debate is at the moment.
Because of the rulings of a couple of judges. Is that actually what the majority of people think?
> Copyright law only considers illegal ownership of a work
That's definitely not true. File sharing, for example, is illegal even if you legally own the original copy you're sharing.
Similarly, copyright has something to say if I read a legal copy of harry potter and then create a new work in that world.
There's a good reason for the law not to be based on what the majority thinks.
Sure i don’t think the majority get to dictate things like who has rights or who the law applies to. That doesn’t apply here tho.