Filter bubbles have always existed in every society, and always will. People have always chosen communities and groups within them with behavioural norms, and those who defy the norms are ostracised or made to comply.

If anything, having means by which communities can separate partially without needing to fully isolate (e.g. if you don't like Twitter's moderation policies your choice is to cut yourself off from Twitter; if you don't like fediverse instance X's moderation policy, you can pick from several thousand other instances with varying degrees of concordance with or opposition to X's moderation policies, most of which can still federate with X) gives an opportunity to reduce those bubbles.

I guess we've got to include some flat earthers in our space programme or we'll never get to Mars. Can't be in a filter bubble, after all.

No one questions that segregated groups with tight information and communication control can result in more efficiently reached results. History has shown us several examples of such highly efficient societies where what can and cannot be said where tightly enforced. But history also has shown us how such societies eventually break from unresolved conflicts within it.

Talking to someone with another viewpoint, even if that viewpoint is a stupid or hateful one, does not mean endorsing. This is not about "fair and balanced", it is about communication and providing ideas outside of their peer group. Now, if you decide to just block flat earthers individually, or as a group (even for non-flat-earth-related communication), you will just create a filter bubble for them in which they can strengthen their now-unchallenged beliefs in.

If someone can come at me with a different opinion that isn't just sealioning/JAQing off, I'll usually listen. The people who are capable of doing that generally aren't on the instances that get blocked. They're normal people on normal people instances who really are curious, and you can usually figure that out with a skim of their timeline.

There really are flat-earthers out there who are easily persuaded by just walking them through an ancient math problem. I've seen it. It's the same way someone who has really bad opinions on marginalized people they've never actually encountered can quickly change their tune by meeting the subject of their ignorance. They're not the ones who collect on the instances that feed off deep, unmovable ignorance.

> The people who are capable of doing that generally aren't on the instances that get blocked.

How would you know, given that those other instances are, you know, blocked?

> who really are curious

Trying to guide the neutral ones into your camp is not a discourse - it's campaigning. In a perfect world we can disagree on topics, and everyone leaves the interaction still disagreeing, but maybe just understand the train of thought of the opposing side.

> with a skim of their timeline.

I've stopped doing that, because all too often, what I find is easily taken out of context and will make people look too "nice", or too "bad". And creating a complete dossier on everyone I interact with online is just too time-intensive.

> They're not the ones who collect on the instances that feed off deep, unmovable ignorance.

Funny how all the blocked ones always seem to be the undesirables, the ignorant, the weird, the stupid, the evil, the ugly, the disease-bearers, isn't it? Of course, wherever we are, the sun shines, everyone is reasonable and happy and friendly to each other. Of course, more often than not, that's not the case. We like to paint the other side as demonic caricatures, because it helps with in-group cohesion.

I don't think guilt by association is a concept that we should keep reviving again and again and again... especially since it appears to me - after having gone through several Mastodon instances - that there are no "normal people instances", that any instance is either radically "free-speech", or it is radically "safe-space".