We need forums where close-minded people with calcified ideas can be challenged.
When there are new thinkers with challenging ideas, you are saying they can just go off in a separate space and talk only to other open minded people.
That's fine for them to do, but it's not enough in the sense that it doesn't reach the people it should. Closed minds can change, if challenged. If. Your suggestion doesn't achieve that.
The scenario you're suggesting is one where most of the people in that sub have chosen to only see the "calcified" ideas. If I was a person who doesn't agree with those ideas, I wouldn't want to stay. A sub with elective moderation is not the forum to challenge people's ideas.
If it's a cat sub, then I wouldn't be surprised if I get moderated out if I'm going there and telling everyone how much better dogs are, even if it's true!
Say it's a sub for politics, if you want real open communication, then you could think about starting a different forum, eg "openminded_politics", and presumably most people who want to use that sub would be open to hearing different ideas.
I'm not sure how else you think it could operate. People who strongly dislike reading differing opinions are not going to read a sub with ideas they are opposed to. You think it's somehow possible to force them to read those ideas?
We need forums where close-minded people with calcified ideas can be challenged.
When there are new thinkers with challenging ideas, you are saying they can just go off in a separate space and talk only to other open minded people.
That's fine for them to do, but it's not enough in the sense that it doesn't reach the people it should. Closed minds can change, if challenged. If. Your suggestion doesn't achieve that.