I can't recommended Nostr to political dissidents because the existing clients compromise peoples privacy to such an extent that they are even more exposed than using Twitter which at least has https (low bar). Clients need to build-in encryption by default.
Discussion
Nostr relays can also work over TLS encrypted connections. In fact most do.
If the relay address starts with wss:// it is encrypted (web socket secure) and ws:// is unencrypted websocket connection.