I think that in the case of something that extends beyond international borders, where the legal definitions can vary greatly, to quibble over the meaning of such a term is needless nitpicking.
I beg to differ. Terms like theft carry a moral weight other infractions do not. Tax evasion can be described as theft using a broad definition, and yet many people wouldn't balk at deducting non eligible expanses. I think using them inappropriately could be way to make things look worse than they really are. It can be an approximation (and therefore it would be nitpicking to point it out) or an hyperbole (and thus deserving pointing out to defuse the rhetorical effect).
Also, it's especially important because it crosses international boundaries to be precise, because several countries can find several solutions to the problem, each adapted to their own situation (no copyright (San Marino), no art [aren't some muslim countries banning the representation of man altogether? or is it a thing of the past], opt-out, opt-in, no AI [Dune?])... There is no reason that what is good for the people of X is good for the people of Y. There are countries that make mandatory things that are forbidden in other and many more examples of things deemed totally harmless in some that are offenses elsewhere. Those countries can be both right at the same time.
I think that the use of people's work, without fair compensation, is ethically, morally, and should be legally abhorrent. There are exceptions in copyright law to allow for the educational use of materials.
By using the word "fair", you're positionning the debate into the field of morality. Everyone is using people's work without fair compensation. We don't pay anything to the inventors of the language we use, to the people who designed the numbers we use... because the law has made boundaries on the limit of time copyright protection applies to. Why is X years fair, and X-1 unfair? It's a tough question, but that's the job of lawmakers to take every view into account and produce texts that are optimal. Also, we are all dwarfs sitting on the shoulders of giants, and nobody would imagine that a scientist who make a breakthrough is a thief because he worked on the ideas of others without compensation. That ideas and concept can't be protected is also legal, but could be seen as unfair by a definiton as wide as "using people's work".
This does not extend to corporations, nor other similar entities.
And would it change anything? What is your stance on open source weights, who by definition don't earn anything to their author? This a concrete example, not an abstract theoretical one, as many very good LLM are open-source.
A "tax" on AI does nothing to compensate the original creator.
No, but it compensate creators in general, who had access to free education in art, free museums with extensive displays to get their inspiration from, public infrastructure like the Internet and grew in peaceful enough countries that they could become artists instead of being enrolled in a militia. Collective compensation is as fair as individual compensation, from a moral perspective, if it is devoted to enrich the social background that made learning artistic skills possible. Car pollutes, fumes diminish the quality of life of people and yet they are not compensated individually, but fuel taxes are devoted (in part) to fund environmental policies, so the damage I sustain by living in a city is compensated by having a natural reserve at the other side of the world. Do you think it's unfair? I don't. A fair compensation doesn't necessarily mean an individual compensation.
Until a levy was placed on the use of digital recording media, in Canada, I used to distribute my work on CD/DVD. The levy goes into a fund that is used to compensate the creators of intellectual property for the unlawful dissemination of their work, in theory. In practice it goes to large production houses. I, as a creator, had to pay it without having any way to get it back, so I modified my delivery methods. I was not being compensated. You can "What if...?" all you like. Mere speculation does little to change my feelings that are based on real experience with such things.
I am not what if'ing. I am proposing solutions, based on existing process not unlike the one you describe. That you felt robbed isn't something I'll dispute, and as a user of CD to store archive of data, I felt robbed by a similar policy of having to pay a tax despite not using it to infringe copyright (in France's case, it's was implemented as a tax on physical media). Interested parties have a hard time determining what's best, because of course their own interest blur the thing. At the time I'd have said "it's not my problem, the artists should just sue whomever is using CD to copy films and music instead of robbing me for using my own data", which was materially unfeasible. It took a lot of restraint to see that it was the a good possible middle ground, especially when funding public policies instead of being reversed to a few "big names" production houses.