You make a few good points, I will try to counter them.

The core idea of the fediverse is the same as democracy - that nobody should control the whole. Both are similar enough to allow comparisons.

True, its for separation of powers but this doesn't mean there cannot be any central rules decided upon. For example the consititution of the united states. However, because the Fediverse doesn't have a government, I think a better analogy would be a league of more or less democractic countries that work together. Of course they can agree to an universal declaration, like the united nations agreed on human rights for exactly the same reasons.

So yes, I think that instances should defederate Threads and encourage other instances to do so. However, they should not do it too hard, to the point that you’re effectively dictating what others should be doing.

Agreed. However, there is a difference between a constitution of a country and agreements between countries. For example, the NATO has an agreement with the US that if any NATO country is attacked, US will jump in. However, this is completely build on trust, if Trump decides to not jump in, no one will be able to stop him, meaning there isn't any higher institution that controls the different actors in this agreement other than the actors themselves. This is why I think the analogue of a league of nations is better, because agreements can be much more loose here.

Of course, there would still be a question who would write this document, but the basic idea would be that if it was supported by many servers, it would be put up more or less by word of mouth. To do this most effectively, it would be good to create the document in a way that many servers willing to agree to it. For example through a ActivityPub commitee that exists anyways or a popular meetup of Fediverse servers. And eventually, the most reasonable one will be hold up by the most servers. I think of it as a dynamic process.

But yeah, there would have to be put some thought into it how to craft it and most likely we don't have the institutions yet to do something like that.

That fallacy has a deep impact across the text because the author believes that people can eventually agree on moral grounds based on reason. Often they don’t - because it depends on the moral premises that each adopt, and moral premises are not true/false matters to begin with.

Could be true, I need to think about this longer. However, I still think that as a foundation, basic fediverse rights could be agreed upon through reason and that they could become effective tools against Meta and to improve the Fediverse in general. Of course, they shouldn't be too detailed and let enough freedoms how to realize them technically.

the actual problem is that the Fediverse is internally shattered and cannot agree on anything, including basic moral rules and principles.

That is not a problem. That’s a feature.

I think its good that different moral rule sets can easily develop and implemented; but I think sooner or later it will become a problem, at the latest when more radical parts become pre-dominant. Its not like the Fediverse will automatically develop in a good direction. I don't believe in a hierarchy-free, anarchic society. We need institutions and agreements to ensure that the Fediverse stays a good place.