There is more than one way to create an echo chamber. You could have a moderator who removes everything which goes against a specific narrative in a community and that community would, by virtue of that moderator's actions, over time become an echo chamber as people who do want to discuss contrary opinions drift away to discuss topics elsewhere.
Yes, that would develop an echo chamber effect.
Alternatively, you could have a concentrated group of users who share a similar view and discuss the same topics over and over again who immediately jump on anyone who shares a contrary opinion. This could lead to people being discouraged from joining said community and create the impression that that specific view represents everyone's opinion. This is more of a "soft filter" than either hard admin action or algorithmic manipulation of post ordering, but it can achieve the same effect. I would argue this is what has happened in the case of the BG 3 forums.
If people are allowed to share their counter opinion for others to see/hear it's not an echo chamber. Situations happen in real life where a person can't change the opinion of the room, even when they're correct. Usually if someone writes out good logic and provides data people will support that opinion. But sadly it doesn't always happen.
Multiple people agreeing doesn't stop other people from accessing the counter-opinion and allows others in the discussion to form their own opinion.
Echo Chamber EffectAn echo chamber is "an environment where a person only encounters information or opinions that reflect and reinforce their own."
