But this is hardly limited to AI.
Copyright is full of grey areas and disagreement over its rules happen all the time. AI is not particularly special in that regard, except perhaps in scale.
Generally the way stuff moves forward is somebody tries something, gets sued and either they win or lose and we move forward from that point.
Ultimately "harm" and "legality" are very different things. Something could be legal and harmful - many things are. In this debate i think different groups are harmed depending on which side that "wins".
If you want to have a nuanced debate, the relavent issue is not if the input works are licensed - they obviously are not, but on the following principles:
- de minimis - is the amount of each individual copyrighted work too small to matter.
- is the AI just extracting "factual" information from the works separate from their presentation. After all each individual work only adjusts the model by a couple bytes. Is it less like copying the work or more like writing a book about the artwork that someone could later use to make a similar work (which would not be copyright infringement if a human did it)
- fair use - complicated, but generally the more "transformative" a work is, the more fair use it would be, and AI is extremely transformative. On the other hand it potentially competes commercially with the original work, which usually means less likely to be fair use (and maybe you could have a mixed outcome here, where the AI generators are fine, but using them to sell competing artwork is not, but other uses are ok).
[Ianal]