This misses two important points about moderation/censorship:

1. I don't want to trawl through garbage to reach posts I like. Even a single gore video or such is enough to ruin most people's day.

2. It's not enough for me to block content I don't like - in certain situations, I have a legitimate need to block others from seeing content I don't like. Specifically, if someone is spreading lies about me, or pornography of me, the fact that I can block that person is not going to help me, I need a way for the platform to stop showing those lies/pornography to others, or at least to automatically attach my own version of the story to those lies (of course, I should first have to somehow prove those are lies).

In a properly decentralised model you’ll be free to subscribe to privately created block lists, which include users and instances considered “unsafe.” You’d subscribe to that and go about your day.

The authoritarian approach is that you want to ensure no one else sees what you don’t like. You don’t want to give them the choice.

So how do I stop people from spreading pornography of me to my friends, family, and employers?

I'm not talking about preventing other people from listening to flat earth conspiracy theories that I don't like.

The same way you should approach any illegal activity: you report it to the police.

Ok, say I win an injunction in court against this image/movie being shared. How is the court system going to enforce this injunction on the Fediverse or Nostr or Blusky?

You don’t need to win any injunctions if the activity is illegal. It will be a criminal case, not civil. The police will handle all prosecution. They’ll go ahead and shut down any suspected illegal activity by order and/or seizure, provided they have jurisdiction. You might just be asked to testify.

The globally distributed nature of the internet complicates jurisdiction, but this has always been true of the internet. If someone uploads porn of you to 300 porn sites and 10,000 tor sites, it’s very difficult to get it all taken down. That doesn’t mean there’s something wrong with the internet. It’s accomplishing its original intent.

Edit: but perhaps that is your complaint? You believe the internet is fundamentally flawed in that there is no central authority which has the power to control all information? I understand the allure of this, but I believe this wound be ruinous for the internet and human progress.

My point is only that some amount of censorship and control of information is necessary. The particular example I gave is actually quite realistic, and happens to many people each day. While getting it off of the whole Internet is hard, getting it off Twitter/Facebook/Google/Reddit/PornHub is, thankfully, quite easy. The fact that it may linger on Tor and some less reputable porn sites or other places for a longer time is not as problematic, since few people access those.

Overall, what I'm saying is that many people who espouse the virtues of decentralized or federated social media forget or minimize some of the actual benefits of centralized social media with strong moderation [0].

While I think it's great that the internet as a whole is uncontrollable, I don't think "living" in the less controlled parts of the internet for most of your online life would be a pleasant or healthy experience.

[0] I should note that I have some serious qualms about the harm some of this content does to the moderators themselves, but I'm not sure how to grapple with that particular issue.

I don't think there is a simple answer to this. I agree that we cannot wish for a world in which nothing can ever be taken down. I guess we're just going to have to find the right balance.

But right now something very conerning is happening in western democracies that threatens to shift the balance very far in an authoritarian direction. And leaning on centralised platforms is at the centre of it.

Platforms are no longer just told "here's this revenge porn video, it's illegal, take it down!". If proposed laws are actually passed it will be more like "if people are discussing stuff on your platform, you better make sure no one comes to harm or else!"

In my view this is a sea change. Pretty soon we may no longer be able to discuss a wide range of subjects on mainstream platforms (such as psychological or health issues for instance). Kids in particular will be severely restricted in who they can talk to about what. In some cases it may prevent harm. In other cases it could be catastrophic.

If the balance moves so dramatically in one direction, I think it is ony reasonable to think about how to mitigate the effects of this to preserve some freedoms and escape hatches. The efforts I see are very very feeble anyway compared to the full force of what we are facing politically.

In my view, no control should ever be total, even if on the whole we cannot wish for a total loss of control.

The tools to do this are still mediocre at best. I want tools to do content-based blocking or defederation, not identity-based.

Not if a decentralized platform claims to be censorship resistant, as Nostr does. But yeah I assume you could just block keys, or IP-addresses at some point.