Better for whom? I think that's condescending. People already know that some forums only contain like-minded people - that's the point! Connecting with like-minded people about some specialized interest is one of the great advantages of the Internet. You can get valuable things out of it, without being under any illusion that you're talking with a diverse crowd.
Maybe the issue is that we don't have enough forums for people who want to have that debate? A "hunting versus animal rights" forum, for example. You'd need really good moderators, though. Lots of people wouldn't be interested in participating, but sometimes there might be interesting posts to reshare.
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 :/
Maybe the issue is that we don't have enough forums for people who want to have that debate? A "hunting versus animal rights" forum, for example. You'd need really good moderators, though. Lots of people wouldn't be interested in participating, but sometimes there might be interesting posts to reshare.