In some ways it's an offshoot of the honest benefit of search engines already crawling all this content. That has its own conflicts, like just how much of a page's content should you reproduce in the results before it's basically considered stealing their content without benefiting the site itself.
There is a balance to strike, both in search engine fair use cases and AI fair use cases. The major cloud LLMs do double as web search engines now, though they didn't originally. In many cases there's no reason left to click the links they sourced from.
That is a legitimate concern. At least within the US, I think there are nuances around fair use and contract law. A lot of companies are getting paid for having their content used in these models, but many websites had no particular rules you had to abide by and the content was simply public. I think if you're operating under an agreement, then even if there is fair use or public domain content being reproduced by the site you are still bound by that agreement.
Similar to old paintings digitized and hosted on some museum website. It's 300 years old, right? It should be public domain, yet the people who digitized it or provided a service to give you access have some say in how their reproduction can be used. These AI services are obviously very different, but there are laws that can govern how you are allowed to use a service if that service has laid out acceptable usage.
I'm not exactly comfortable with the mass scale that everything was soaked up to train these models even within the umbrella of search services, but I also admit that a lot of the usage was probably quite legal. The potential displacement caused by the resulting trained models on artists or writers is almost its own facet. In practice, whether they ONLY trained on strictly legally acquired fair use content with no errors and paid agreements to acquire even more content than they already do or not, there was enough legally accessible information for fair use that there was no escaping some kind of impact on artists, writers, etc.
With any luck, artforms and skills impacted by technology will adapt and continue to be valuable instead of complete displacement or the dilution of opportunity.