I must admit, I don't worry too much about this scenario because I don't see any way for Bitcoin to have any real impact in a country where using it is illegal. There are about a million ways a government can round up Bitcoin users beyond strange mathematical games - most obviously, find anyone advertising a price in Bitcoins and punish them. For people to use Bitcoin they have to be able to spend it, and to be able to spend it you need to find merchants willing to accept it, and for a merchant to accept it requires advertising that fact.

If you think brute forcing salted passport hashes is the easiest way to crack down on Bitcoin, then that implies you believe the government has no ability to just go into the marketplace and use undercover agents to ask around. Seems unlikely. Also remember you could just not run nodes in that country, or run them but without providing passport proofs (you could provide a sacrifice proof instead, or no anti-sybil data at all).

Also - maybe this isn't obvious, but I write my talks to be interesting, not as a cast-iron manifesto of things that are guaranteed to happen. Using zk-SNARKS to prove ownership of a passport for anti-sybil purposes is an interesting idea, but that doesn't mean it'll actually ever be implemented. We can't even prototype it today!

FYI I agree that Satoshi was probably not a hard core crypto anarchist. He started to back away from the project around the time people were suggesting WikiLeaks should accept donations with it (what he called "kicking the hornets nest"). I doubt he would have been happy about the Silk Road, which opened just two months after he stopped posting publicly.