Earlier quoted context omitted.
I'm very much in favor of leveraging the advantages of version control software for legal text. Git seems perfect for this, but GitHub is a terrible choice to host it. Surely we don't want a large corporation owning the platform on which our laws are enshrined. It seems like it would be much better for this to be self-hosted.
Git is decentralized so it doesn't really matter where it's hosted. Github works since it's free, but everyone who checks out the source will have the full git history and so also becomes another repository. Easy to move a git repo to somewhere else.
If we are talking about accepting PRs for drafting legislation in git, where it is hosted and who hosts it becomes extremely important. Sure anyone can clone/fork, but only the appointed central repo could become law. A clone that you or I make will likely never have this ability.