But you are evading. The technicalities you speak of are irrelevant to the topic of censorship. The fact that parts of BlueSky are technically open source, or that other BlueSky apps exist is irrelevant to the people who are functionally denied access to speak due to the decision of a single company. There is no other "instance" we can go sign up on like with ActivityPub apps.
(Here is the part where you say I could technically get all my friends to self-host their own PDS as though it is easy and fun).
incorrect actually