Anyone who owns a server can access all the data stored on it, unless the data is end-to-end encrypted. Whether it's mastodon, Lemmy, Facebook, twitter, Gmail, vBulletin, whatever.
If you need to say something that you can't risk anyone else seeing, use an end-to-end encrypted messaging app, or implement encryption yourself using e.g. PGP.
The web client supports it too, as do other apps like Tusky and Ivory. The official app is just a weird outlier.
Since they say that all their content moderation is currently being done by two backend devs on top of their actual jobs, that seems like a safe bet.
I think pixelfed added video very recently
Not at all! We just need a combination of A) more new instances popping up, B) some people moving to other instances because they like them better or they run faster, and C) kbin.social admins scaling up this instance. It's just an adjustment process.
The good thing about fediverse services is that as long as there are people willing to throw up a server, you can just keep scaling - unlike on a centralised service where if the owner doesn't scale, that's tough.
I don't think we're heading towards an everything app, but we may well see an everything account at some point. Companies already use social media management portals to post/respond on multiple platforms; I think if that kind of commercial demand arises for fediverse services, we will probably see similar fediverse management portals which allow you to interact with content on multiple ActivityPub services in a context-sensitive way via one account.