I'm well aware of previous incidents, which is my basis for why GitHub is the platform that can cause so much damage to the Chinese government. We both seem to agree that China is very dependent on GitHub (perhaps the only western website they still rely on) and the economic damage of being forced to block it would be astronomical.

What I suggested and GreatFire is miles apart. Moreover, I'm not saying that throwing up some wikipedia articles about Tiananmen, Chairman Mao, etc. will result in China being forced to block GitHub or attack you. The path to success is to have the repo spread to tens of millions of Chinese locals. Regular people, not just the tech savvy that knows what a VPN is. It certainly won't be easy, especially considering they can easily shadowblock all links to the repo, the name of the repo, a picture with a link/QR, etc.

By the way, people have already been and continue to be tracked down and attacked for doing these kinds of things (a notably incident that reached the front page of HN: https://news.ycombinator.com/item?id=10101469), so no, the assumption that people will be attacked for doing this is most definitely not wrong.