Just a random idea: perhaps we should extend democracy to the spreading of information. I.e. you can spread information but only if the majority of people agree with it. (A post is evaluated/moderated by a small group, then a bigger group, etc., until perhaps it reaches the entire population). Moderation is not limited to groups, so echo chambers would not have a chance. EDIT: minorities still have a chance in two wa…
I'm old enough to remember when the government made it illegal to mention homosexuality in schools. And when it was illegal for a particular elected MP to speak on television.
Even today, there are teachers who spout that homosexuality is somehow a bad thing.
Controversial topics will take time to reach mainstream agreement, no matter how you shape the spread of information. The question is how to do it in a way such that society is not disrupted by a strong opinion.