At the risk of answering a rhetorical question: because copyright covers four rights: copying, distribution, creation of derivative works, and public performance, and LLM training doesn't fit cleanly into any of these, which is why many think copying-for-the-purpose-of-training might be fair use (courts have yet to rule here).
I think the most sane outcome would be to find that:
- Training is fair use
- Direct, automated output of AI models cannot be copyrighted (I think this has already been ruled on[0] in the US).
- Use of an genAI to create works that would otherwise be considered a "derivative work" under copyright law can still be challenged under copyright.
The end result here would be that AI can continue to be a useful tool, but artists still have legal teeth to come after folks using the tool to create infringing works.
Of course, determining whether a work is similar enough to be considered infringing remains a horribly difficult challenge, but that's nothing new[1], and will continue to hinge on how courts assess the four factors that govern fair use[2].
[0]: https://www.reuters.com/legal/ai-generated-art-cannot-receiv...
[1]: https://www.npr.org/2023/05/18/1176881182/supreme-court-side...
[2]: https://fairuse.stanford.edu/overview/fair-use/four-factors/
To me this is a strong point in favor of the idea that OpenAI has no business using their work. How can you even think it's ok for OpenAI to use work that was not done for them without paying some kind of license? They aren't entitled to the free labor of everyone on the internet!