Lots of projects have had requirements like this for years, usually to prevent infection by (A)GPL's virality, or in the case of the FSF, so they can sue on your behalf, or less scrupulously, so the project can re-license itself or dual license itself in the future should the maintainers opt to. (This last part was traditionally the only part that elicited objections to CLAs.)

> it's like a high tech pinky swear

So is you attesting you didn't contribute any GPL'd code (which, incidentally, you arguably can't do if you're using LLMs trained on GPL'd code), and no one seemed to have issues with that, yet when it's extended to LLMs, the concern trolling starts in earnest. It's also legally binding .