It was supposed to be decentralised though, meaning there would be no central party to pursue.

Sure, which is why it's perfectly possible to work around those restrictions using any of the alternative apps that show the same data (but don't implement the legal restrictions).

It is. The block is on the client level, not the network.

What makes you think a nation state level entity can't pursue in this case...?

The same reason even nation state actors have not managed to eradicate torrents. You take one tracker down, another pops back up.