I don't think the focus on 'calamitous design choices in git' is worth its spot in the articles headline. While, yes, they do say that, it's a very short throwaway with no substance. The real meat of the content in the original post by the developers is the conflict between distrust of centralizing and the "hacker spirit" with the pragmatic realization that it's a lot of work to keep yourself independent, and that, in the end, it's not worth it to them. Github is easy, github works, github is clean, and so they decided github is the solution.

It’s not just Bugzilla. It’s the wiki, the mailing lists, the quaint little Mercurial web interface. The little open source thing that we rely on but no one is working on and probably has security holes in it. It’s all janky, and it causes developer friction. It causes it for Sam and I, and we’re old Unix command line cowboys, so for those that expect computers to treat them like computers do in 2021–with slick UIs and without cronjobs that occasionally fail until Ryan rolls along to restart a service over ssh–it was becoming untenable.

So in moving it to GitHub, we’re finding that a lot of things are just nicer because a large paid staff of engineers is working on it every day. And I grew up during the heyday of the Free Software Foundation, so I know this is a trap, but I’m tired and don’t have the energy to be a server admin for something that’s held together with scotch tape and prayers when I’m really supposed to be writing OpenGL code.

I think it's a little bit strange that they did a hard 180 from Mercurial + mailing lists to git + GitHub, when they could have modernized the existing infrastructure with something like SourceHut. Maybe because SourceHut isn't very well-known or battle-tested yet?