I have been saying a number of times over the course of my time here, that I think the "echo chamber"-ness of Lemmy is by design.
Each instance is moderated by a different team of people who run their server under a different philosophy. You can see clearly in this thread many from the lemmy.ml instance express mild disdain for "liberals", whereas other instances like lemmy.world and lemm.ee don't hold such animosity to that collective extent, but admins hold other expectations for what should be the norm. The way I view the Fediverse is that it's a collection of echo chambers, which within them help foster discussion between like-minded individuals. However these are networked with each other so you can wander outside that bubble to other instances when you feel like it. You also have control to block groups and instances you don't vibe with.
I know some instance moderation policies remove posts and comments that go far against the grain, but in other instances, unpopular takes just get super downvoted but left for people to see.