We can't 'fix' echo chambers nor should we want to. People should be allowed to use the internet how they like when it comes to communication and social services. There is nothing wrong with like-minded people coming together to form a community to support something.

Does it suck that sometimes that thing happens to be an ideology, extreme political stance, religion, drug, and every other 'bad' thing under the sun we don't personally like? Yeah, sometimes I see a community for something I personally don't like and wish there wasn't one based around it. Does it suck that some communities exist for nasty, hateful, willfully ignorant individuals to openly share their bad takes? Yeah.

That doesn't mean they should not have a right to congregate together on their own privately operated fourms funded and upkeeped by their own members. The nice thing about lemmy instances and the fediverse is that we can defederate entire instances. Its a great sweet spot between not seeing or interacting with hateful echo chambers filled with negative angry people and not infringing on their right to still exist.