@blaine an outside moderation tool will, I think?, always have less granularity than the instances' preferences granularities. As in, you could have a vendor provide a few specialized views into the fedi, but any shared blocklist is going to have some amount of misalignment with any specific instance's preferences.
I wonder if there's a way to share moderation decisions by weighting the influence of neighboring nodes in an affinity graph. (this isn't the same as the federation graph, ragelove might be willing to federate with fosstodon but have no trust in their moderation decisions.) If aleph high-trusts ragelove, and ragelove defeds naziparty, how can aleph benefit from that decision automatically? Maybe if multiple high-trust peers send along the same moderation recommendation, or several medium-trust peers, etc.
(This sounds kinda like "whuffie" in an early Cory Doctorow novel. I may be cyberpunkpoisoned by reading it during an impressionable period.)