OK, so apparently I shouldn’t have said “beyond the obvious,” and the obvious needs stating:
(1) Copyright licenses very clearly •do• allow the copyright holder to determine who may use a work and for what purposes, at least when such use would be otherwise prohibited without a license. That is how the law works. Rightly or wrongly, empires are built on this: “Streaming service XYZ may offer this song for streaming but not for download until this date.” Copyleft is one example of this principle in action.
(1a) Thing the thing presents discriminatory licensing (such as in Daniel’s strawmen) is anti-discrimination law, not copyright law.
(2) The reason copyleft specifically might prevent LLM usage is that •if• LLM output can be considered a derived work of the training material, then the output must also be licensed in the same way. That seems to me a thin reed: courts so far haven’t been willing to treat LLM output as derived work, even when the output includes things that would surely be considered plagiarism and grossly illegal if done by a human. But I don’t see another path to protection, and courts are still sorting this out…so.
https://mastodon.sdf.org/@dlakelan/116267990581623218