Happy to be corrected, but according to these two websites [1] [2], the maintainers that were booted were Andrew Robbins and Sebastian Grzywna, and that happened two years before Adrien Bourmault and Denis Carikli created libreboot.at.

Libreboot.at itself seems to be a reaction to binary-blobs, not to this other drama.

[1] https://www.andrewrobbins.info/libreboot.html

[2] https://web.archive.org/web/20210331005023/https://libreboot...

Unless there was a third "abandonment" and a "takeover" after that, I don't see how those events are related. Once again, happy to be corrected.