It really won’t. Ignored posters don’t get flagged. If someone wants to post a well-reasoned message about why they think keeping children in cages is sound national policy, have at it. Those that ignore them, will not see the post and not respond. Others will (very likely) vociferously debate them. While some may flag the post because they disagree with the idea, the mods will not allow the flags to stand if the post is otherwise within the guidelines.
That does not mean that the post deserves agreement, or any response at all, nor would we ever try to force individuals to read something they choose not to. It seems to me that a lot of the complaints around “echo chambers” fall into these categories, and they are doomed to fail. Just because someone wrote something doesn’t mean anyone will care, and especially doesn’t mean that anyone will agree.
When I see someone suggest that they choose not to post an unpopular viewpoint, my first response is: “well then you are creating the echo chamber”. Because to me, what they are really saying is “I should have an open forum to post opposing viewpoints without having to deal with contrary opinions”, which, frankly, is not an open forum.
If you are discouraged to post opposing views because you know they will be unpopular, that’s not an echo chamber. That’s an unpopular view. And you have every right to post them here (within the rules). But, everyone else has a right to respond, too.