I suspect that moderation is something that “AI” may eventually be quite good at.
But human or machine, open or closed, moderation will always be biased. Each community will have its culture, and moderation will reflect that.
A community of Nazis will moderate out stuff that many places would welcome. Some communities would moderate anything not cats on Roombas.
HN is one of the best-moderated communities I’ve ever seen, yet, it has its biases. Organic moderation reflects cultural biases. I’m not always happy about what gets put on the chopping block, but I usually can’t argue with it, even if I don’t like it, or am cynical about why it’s nuked. I stick with HN, because, for the most part, I don’t mind what gets moderated. The showdead thing lets me see what gets nuked, but I usually like to leave it off. I’m not really one for gazing into the toilet.
The main thing that an open fediverse can bring, is transparent moderation, so folks will know when stuff is being blocked, and can use that knowledge to decide whether or not to remain in the community, or advocate for change.