These blocks can be circumvented, and so far they have been, but freedom is generally on the defensive here.

This weakness has become especially apparent in recent years when governments react to civil unrest or protests by shutting off the internet. Signal doesn't help much when the data pipes stop flowing.

I recall hearing about another privacy-focused messaging app that could be used peer-to-peer with Bluetooth, though I cannot recall its name. Edit: I think it was Briar? Not something I'm familiar with.