Cool! I'll save that tool. Mike's link: "What does blocking do? Blocking prevents interaction. When you block an account, both you and the other account will no longer be able to SEE OR or interact with each other’s posts." That sounds like the blockee can't see my future posts, doesn't it?
...And wouldn't that make sense? If you choose not to interact, why would you block your view that still lets that blockee see and then slander you on third parties? If you don't want to interact, the view really has to be blocked two-way.
That quote's specifically about the user-facing Bluesky app (bsky.app), rather than the underlying AT Protocol. As for *why* (almost) everything is public, it's because Bluesky/ATProto needs it to be for federation/decentralization to work.
For example: if Elon Musk somehow manages to buy Bluesky and run it into the ground like he's doing with Twitter, you and I would still be able to run our own servers and move all our data off of Bluesky's servers and onto ours, thanks to ATProto's federation features.