the fediverse blocking off people who want to join it seems odd. Like, we want the fediverse to be a thing so that everything can talk to everything else and the content itself can be king without having to worry too much about where that content lives.

Not me. I wanted something free from multibillion dollar corporations. And people aren't blocked off. They don't even need an account to view content or an app. And they aren't blocked from creating a non meta affiliated account if they want to participate.