> posts, likes, comments, reacts, boosts, quotes
It sounds simple, but when you think about the details, it's a very complex problem full of problems that you have to solve... for example, when a bridged user quotes a post of a user who is not bridged, and there is dozens or hundreds similar problems.
And whats worst - It usually leads to centralization, that someone has to run those bridges and have the private keys to all those "pseudo" identities. For me, it's just not worth it.