The tradeoffs Bluesky made to achieve that means that Bluesky doesn’t have private posts. In fact, Bluesky doesn’t have private blocks.
It’s two way bridging. The issue is that Bluesky users also must opt-in to having their posts be bridged to Mastodon (by following @ap.brid.gy).
I actually still don’t understand why one would be in favor of federation but opposed to bridging. In esscence, bridging is just federation.
Why?
I do wish that Lemmy instances would do this.
There are already “other Blueskies” out there, and you can already port your identity to them.
However, most users haven’t, and most users are not motivated to do so. Thus, OP created a website.