I haven't looked into the protocol in any depth yet but it does seem like it supports end-to-end encrypted updates.

What data are you talking about that can easily be crawled without any permissions?

If it is that simple then maybe Scuttlebutt isn't a good protocol, but a secure end-to-end platform like this is definitely possible. And if anyone is going to build it it's not going to be a company who makes all of their cash from harvesting user data.

I've written a partial implementation of the scuttlebutt p2p protocol (not the encryption, but everything on top). While point to point is encrypted, the bulk of the data is not encrypted. You can specifically send "private" messages that are encrypted such that only a set of keys (users) can decrypt (read) them, but this is by no means the default for anything.

So the feed is public like Twitter?

essentially public, and also basically requires downloading and storing the entire history of a "feed" to verify it.

Sure you can download everything, but you can't read it...

you can read 90+% of it (only specifically private messages are unreadable, and most of the systems are not built on those)