They don’t care about copyleft or “information wants to be free”. They want a feed that isn’t full of Nazis and that all their friends post on
They don’t want to think about platforms, peering, distribution, server mutes, or any of that faff.
If you're hosting people who already have a large audience, or are especially vulnerable to harassment, that's probably going to happen sooner or later and it would be wise to craft or copy a denylist before it does.
I run my own Mastodon server and I've never had to take any moderation actions with a few hundred followers. I know the names of a few vile servers and can't recall seeing them among my followers. I suspect I'm fortunate in just not being interesting enough to vile people.
If the admin blocks an instance it's either a community you as a user won't want to be interacting with, or the user has chosen the wrong instance for them to be on.
I don't know why people say that every instance not federating with every other is a bad thing. It's not. I definitely don't want to interact with the extreme right instances around so I choose one that I feel at home with and that has them all blocked. I think that's the beauty of the system.
I have not seen any evidence of any major instance ban another instance because it refuses to ban yet another instance. There would be no reason for that. Messages from the controversial instance still won't make it to the instance that demands the 'virtual signaling' even through my instance.. unless some user on my instance essentailly quotes whole posts.
It may be that most of my circle has migrated over to Bluesky and the only people left on Icelandic twitter are either public figures or nazis. So the nazi content is just a greater proportion of the diminished Icelandic content. Or that nazis feel empowered inside the current Twitter atmosphere, which honestly is very scary to think of. I tend to think that the reason is a mix of both.
Then Elon turned off the app access and I had to use the official app. There they were! White supremacists, algorithmically injected straight into my feed.