The "problem" with this stuff is it doesn't really work. There will always be an incentive to abuse the list and add people over personal gripes, and everyone else who is party to the list needs to reach absolute consensus in every case.

Every construct like this will sooner or later lead to the maintainers exhausting themselves and splitting up in an orgy of drama.

The only people who really suffer from this are the ones on these instances with restrictive policies - who don't realize they can just walk away, and of course the ones stuck on central platforms because "omg mastodon is insufferable"...