The penalty for wrongthink on mastodon is banning. This ensures ideological homogeneity within each instance. For many people, this is a feature not a bug.
Thing about an echo chamber is that it feels amazing to be in one. Everyone agreeing with me, slapping my back when I say something to reinforce the groupthink. I feel so smart! Love it!
The negatives of the echo chamber are felt by people not in it, not me and my group.