The important part are the big circles in the bottom left. The PDS is an instance. Instead of transmitting content directly to one another, they communicate through giant content aggregators called BGS, which is owned by Blue Sky. These are radically inefficient by design, so only big companies will be able to run the BGS.

Basically, it would be like if everything you poasted had to go through an instance like Poast or Mastodon Social first to federate to other instances. It’s not censorship resistant at all. It’s barely decentralized.