

I like the idea. Better yet: Don’t put it on top, but make it part of the platform itself. I think moderation is an integral part of a platform and should be baked in.
And another idea: Some other platforms have moderation be some kind of feed. We could expose moderation decisions as some kind of feed people can subscribe to. That way I could say: I trust team XY to do the moderation for me. And someone else could subscribe to a different “court” or team of moderators who are more or less strict. I kinda like that idea as well. But it’s also guaranteed to be (ab)used for the usual political, online ideology/identity war. Not sure if that’s a bad thing or a good thing.
If you combine both concepts, you’d get a solution which isn’t “central”. And it offers customizability to the users, and/or individual instance admins.

I think 1) and 2) are kind of what makes the Fediverse fun. We’re not just an accumulation of sometimes compatible servers. We do make an effort to span one big, interoperable network and put in the effort to standardise and find common solutions. And we also try to offer means to individualise the experience on different instances.
I’m afraid we also have additional issues with different jurisdictions. I mean I’m a server operator based in Germany. I have different rules for hate speech than for example someone based in the USA. How I can and can’t phrase certain things. The UK has some different/strict internet laws. And someone from Japan for example has a whole different set of rules for some kinds of posts… It’d be difficult to come up with a central solution which isn’t some lowest common denominator. Which probably will be overblocking in this case?