In general, yes, Bluesky's architecture and moderation design is very different. Defederation is nowhere near as central as on the fediverse. Servers in general are not expected to define "communities" like on the fediverse. They're more like shared web hosts: customers may see each other occasionally on the support forums, but in general they're independent.

Also, as a server admin, the posts your users see in their feeds never touch your server at all! They go from AppViews directly to your users' clients.

In general, Bluesky server (PDS) admins have significantly less power and responsibility than fediverse admins. They can moderate their own users, but they generally can't moderate what their users see, nor are they obligated or expected to. Those decisions are made by mod services (née labelers), and then by AppViews, clients, and users who all choose which labels to filter out.

This can all still be just as administrative as the fediverse! Everyone expects and is planning for mod services, AppViews, and clients to have strong defaults for moderation. But yes, that moderation and those defaults all happens independently from server admins.

The fediverse has a good model for content moderation, and federation in general, but it's far from perfect. It's very inflexible and one-dimensional: everything is on server admins, for better or worse. Personally, I think it's great seeing more people experiment with more models. We'll see how it goes.