Serious question: What is the point?
Just push into half a dozen mirrors and you are pretty censorship resident without the crypto voodoo put on top of git.
Github has one huge value: Discoverability of a project. This is even worse than hiding your project in one of the smaller forges... nobody can remember the mess of letters you need for this.
The blocking certain countries is a US legal thing. It effects any forge in the US and probably in more areas close to the US. As soon as a forge gets big enough to show up on the radar of government orge they will need to do similar blocking.
You can not really blame github for that part.