> If a post is flat out illegal, the authorities will go after the person responsible, NOT the platform, NOT the nodes.

Governments are sovereign.
They can go after whomever they wish, within the limits of their own laws which they can make and change to fit their needs.

Indeed, Nostr is censorship-resistant in a way that mainstream platforms are not, in the sense that it protects us from corporate censorship.
This is good, we shouldn't filter what we read and write through the erratic whims of a few billionaires dictated by their selfish economic interests.

But Nostr doesn't stop government censorship.
You are right when you say authorities can go after the poster.
But authorities absolutely can go after Nostr relays within their territories, too.

I hope it won't become a problem and, if it does, it can probably be solved similarly to how mainstream platforms solved it, but Nostr doesn't prevent governments from going after relays. 

 Valid points.