If the average person is completely shielded from any kind of discourse surrounding their beliefs, society will suffer. Echo chambers are the main reason politics in the US have become a complete disaster. When you hear the other side's point of view presented by your side, it's going to be biased and will just reinforce your own beliefs.
As evidence of this, think of how many people think that $other_party wants to "destroy America" in some form. Cue (and possibly queue) commenters saying "but $x really does want that!"
I've found that people who claim to know the other side's motivations are projecting for the most part. I catch myself doing it too. Being more aware of bias does not make one less susceptible to it, unfortunately. If anything, it tends to bring overconfidence regarding it :/
