Snowden lives in Russia. Russia is not keen on nostr for sure. Purely speculating of course, but would make sense. Pretty sure he ain't completely free in what he promotes.
It's sad that nostr:nprofile1qqsgfhhxuemwtwm8kjk5uppv7uxtmp5pz4wm2dv59lxx5pfnsk98ysqpzamhxue69uhhyetvv9ujumn0wd68ytnzv9hxgtcp0q5vq is inactive on nostr, but very active on twitter.
He and nostr:nprofile1qqsgydql3q4ka27d9wnlrmus4tvkrnc8ftc4h8h5fgyln54gl0a7dgspzemhxue69uhhyetvv9ujuurjd9kkzmpwdejhgqg5waehxw309aex2mrp0yhxgctdw4eju6t0qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyfehcpn bootstrapped nostr advertising it on twitter and caused a massive influx of users.
That's a pity that he made that choice :(
Discussion
I hear what you're saying, but Snowden doesn't strike me as the guy who let the government dictate what he must and mustn't do.
I just think it's a question of reachability.
Nostr is cool but its userbase pales on front of the Twitter's one.