Nope... or at least not 100% ... as it is still based on the use of DNS..
if someone shuts down a domain name (ref. autistici.org case in Italy closed by US government just telling https://pir.org/ to do so) is not a big issue as there are lot of relays, but if who has the power to block alot of domain names with a single action even Nostr can have hard time..
