the centralised hosting of a git server is much less of a big deal than it first seems. It is trivial to switch from one git server to another. If a contributor is blocked from accessing a git server, they can access an mirror with identical functionality. Only a small number of repo maintainers need write access.

Decentralising the code collaboration surrounding the repository on the other hand is much more important. If a contributor is blocked from a centralized service here really stunts there ability to contribute. If a repository gets banned, it be very disruptive for the project. They have to scramble to choose an (often centralised) alternative, they may have many PRs in flight and the conversation around these may be lost.