Why GitHub? If they truly cared about open-source they would've chosen something else, such as a self-hosted Forgejo [1], or its most common public instance Codeberg [2].
[1] https://forgejo.org/
[2] https://codeberg.org/
I would argue that part of "truly caring" about open-source is being where the contributors and community are. That's probably a large part of the move to GitHub, and neither of these other options would achieve that. As much as one can say "git is distributed, the server doesn't matter", the centre of the community very much does matter, and for better or worse that's currently Github.