In AT you also get communities, in the same way that twitter had weird twitter, black twitter, and so on. But because you, by design, don't really see what PDS people use, it's more fluid.
I personally think that this actually leads to healthier communities but that may be a matter of taste!
Yeah, I mean a big reason why Fedi is segmented the way it is, is because the Mastodon crowd has a lot of merited and unmerited prejudices against the other parts of the network, and put a lot of effort into splitting it with centralized blocklists. The W3C working group that works with the AP spec (which refuses to cooperate with credible people representative of projects like Pleroma) is now looking to adopt a centralized moderation model similar to Bluesky's. It's one of the issues with the instance model, even though users have the tools to shape their own view of the network, to not have to see things they don't like, instance admins still get to dictate who they're allowed to talk to and what they see. I don't think that's right, even if the reasons are justifiable.
The guy who runs FSE (one of dark fedi's more notable instances) has written a lot of good blog posts on his side of the technical and social details, his one about running FediList is a good picture of the type of one-sided politics involved (and, if you're into the technical stuff, is rich with that too): https://blog.freespeechextremist.com/blog/about-fedilist.htm...