My guess would be they can't be brothered. Government does not have unlimited resources and depend on submission based on fear for compliance. Really in truth no government can ban most things if people really decide they want to do it.

Another theory is there is selective enforcement but this seems less likely to me. Curious what others think.

Another reason could be IP hopping. Very possible the state blocks IPs but miners get new ones.

I'm also skeptical of geolocation data based on IP addresses in general. Its complicated.

I wonder how Tor and other privacy tech works in China. Does Signal work for example? Do they block those IPs?