Surly blacklists should be democratised or at least per instance democratised. Anything else is the equivilent to handing the fediverse over to some private entity and giving them extrordinary power.
How do you democratize something when one person owns and pays for the hardware where your instance is? The moment the vote doesn't suit them they can just overrule it. By being on a fediverse, unless you are hosting your instance yourself, you are literally under complete control of some other individual. Lemmy.world and kbin could tomorrow block each other and there's nothing the two of us can do except either comply or leave.
There's no way to transfer accounts afaik, and just hopping instances doesn't solve the web of blocked / blacklisted domains anyway.
As for hosting it yourself, that's apparently really hard and even big communities are struggling with it. Lemmy/kbin also have issues with all the content you interact with being also downloaded to your instance which sounds like a legal and curation nightmare...
Also, "democracy" on a platform where anyone can have as many accounts across as many instances as they want is doomed. If anything you'd just be offering those power-tripping, time-flush aholes an extra veneer of legitimacy.
I don't believe for a second that 90% of top posts aren't already being manipulated to some degree, even if just by an individual with a bunch of extra accounts. It's just too easy to do for it not to be the case.
It's not really feasible to hold a vote on a decision like this when users can make endless socks. But it's not really needed too.
Blacklist decisions are democratized in that the most popular instances can choose or not to participate in it. And if the users don't like that the instance is a part of the block list they can create an account on another instance that doesn't participate in it. If an alternate blacklist that doesn't arbitrarily block instances based on the whims of the maintainers is created then the popular instances are going to switch to it if it becomes popular or users will go to an instance that does.
The fediverse is a free platform and users vote with where their activity is.