Sorry for the late response, I fell asleep.

Yeah I'm concerned about that too. It really doesn't matter what anyone does if a group the size of Meta joins the fediverse though. They have tens of thousands of engineers working for them, and billions of users, they can do whatever the hell they want and it'll completely swamp anyone else's efforts.

Zuck wanting to embrace, extend, and extinguish the ActivityPub protocol is a separate issue though. The way a chain of trust works, when you grant trust to a third party, they can then extend trust to anyone they want. So for instance, if the root authority "A" grants trust to a second party "B", then "B" can grant trust to "C", "D", and "E". If "A" has a problem with the users of "E", the only recourse he has is to talk to "B" and try to get them to remove "E", or ban "B" through "E" altogether. I think we can both agree that the latter action is super drastic, it mirrors what Behaw did, and will piss a lot of people off.

So if you run that experiment, and any particular group can become a "root" set of authority for the network, I'd speculate that the most moderate administrators will likely end up being the most widely used over time. It's kinda playing out like that at a small scale right now with the Behaw/Lemmy.world split. Lemmy.world is becoming the larger instance, Behaws still there but just smaller and more moderated.

People can pick the whitelists they want to subscribe to. Who gets to participate in a network really just comes down to the values of the people running and participating in it. A chain of trust is just a way to scale people's values in a formal way.