Even if you do that, what's to stop them from using open source software from all over the web and not just what's on GitHub? The only way to stop them then is to go closed source.
I mean stop them at a larger level by threatening their success as an organization. If developers stop publishing to GitHub they have bigger problems than training ML models.
Whether or not this move is “legal”, it should serve as a wake up call that GH is not actually a service we should be empowering. This incident is just one example of why that’s a bad idea.
