alt Hacker NewsATproto federates in a very different way than Mastodon. There is no concept of "instances" on ATproto.
Your account is hosted on a PDS and you sign into the app with your PDS sign-in and records go to your PDS, but everything on the app is from what's called an "AppView" which provides a centralized view of all data in all PDSes so it feels just like you're using a regular centralized app. But there can be multiple AppViews and AppViews can be self-hosted.
So unlike with Mastodon, it doesn't matter what PDS "instance" you're on because the app layer is completely separate from it.
> There is no concept of "instances" on ATproto.
Regardless of name and precise technical details, there are central service components that can ban you. If a proper ecosystem of those ever springs up then the equivalent of fediblock (ie guilt by association) oriented at individual accounts or PDS is the next logical step. At present (last I checked) there's only (approximately) one primary provider plus blacksky making the situation even worse.
This isn't some wild hypothetical - we also see guilt by association in the matrix ecosystem.