or AI scraping is not fair use, in which case they already have the copyright.
What? How would an AI company have copyright over @onlinepersona@programming.dev’s comment? That makes no sense at all.
It’s the other way around, onlinepersona already has the copyright. Asserting that the copyright is non-commercial changes nothing. The default is non-commercial. The default is nobody can use it. They are applying a more permissive copyright than the default.