> > where the affected users might be surprised or alarmed to learn that it is possible to link these real-world identities.

> I feel like it's obvious that ssh public keys publically identifies me, and if I don't want that, I can make different keys for different sites.

You're probably not the only one for whom it's obvious, but it appears to be not at all obvious to large numbers of users.

ssh by default sends all your public keys to a server. Yes you can limit some keys to specific hosts but it's very easy to dox yourself.