* Your PDS is like your own website.
* Bluesky is like a search engine.
* plc.directory is like DNS.
If you choose to have someone host your own web site, then it's up to them what happens to it. You're using their servers after all. If you have your own host, you get to decide what happens there.
Likewise, a search engine can say "hey, I don't like what's happening on that website, so I won't surface it in results," but they cannot shut your website down.
Now, the only twist here is that currently, atproto is kind of like if there was only one real DNS server, and it was also owned by your search engine. That is, BlueSky the company runs plc.directory. So in the maximal sense, "if you run your own server" is technically "and you only get an IP address, not a domain name," that is, if plc.directory decides to unlist you, then folks can't find your posts. There is an alternative to plc.directory, but basically nobody actually uses it at the moment.
Okay, so on a technical level, that's the rough explanation. On the social level:
Here's what they have to say: https://docs.bsky.app/docs/advanced-guides/atproto#speech-re...
> Atproto's model is that speech and reach should be two separate layers, built to work with each other. The “speech” layer should remain permissive, distributing authority and designed to ensure everyone has a voice. The “reach” layer lives on top, built for flexibility and designed to scale.
> The base layer of atproto (personal data repositories and federated networking) creates a common space for speech where everyone is free to participate, analogous to the Web where anyone can put up a website. The indexing services then enable reach by aggregating content from the network, analogous to a search engine.
On the PDSes that Bluesky hosts, they will remove illegal content, but nothing else. That's the "speech" part. However, they do moderate Bluesky itself, and there's a gradient there: they will remove some things, they will also tag some things, allowing users to decide if they want to see it or not.
As far as the "DNS problem," they've stated that they wish to move it into an external foundation, to build additional safeguards there. I personally believe them, because they have promised many things, including things that have reduced their own power and control over the network, many times, and then followed through. You can choose to believe them or not, or wait until it's the case before getting invovled.