It is fair to say that these isn't that much diversity. I see a lot of anti-state memes, pro-bitcoin memes, nostr dev talk, etc. But I feel that this is normal, because that's what the people on here care about.

How do you encourage people to talk about their other interests to manufacture said diversity? I don't see how you can. 

 Twitter Bitcoin "influencers" don't really care about #Bitcoin or #Freedom, they just pretend. Otherwise they would have jumped to #Nostr, or at the very least, mirror posts on both places, manually or with a bot.

Nostr clients are getting decent, #Snort and #Primal for example are very identical to Twitter UI/UX. And you can find content via hashtags. 

 Even if that were true, I can't really fault someone for doing their job. 

The vast majority of people you have a chance of convincing to use Bitcoin and Nostr are not here, they are out there on other platforms.

Regarding your point about the mirror. Yea, you're right, they probably could do that.  However, it takes time and effort to set those things up.