Ironically the reason why people see this about Nostr and choose to leave is the same reason why Nostr can seem like it's the very echo chamber they talk about. If you really want to make a difference, join and present your views to counter them and make content more diverse. That's the free market of ideas that Nostr presents.

“If there be time to expose through discussion, the falsehoods and fallacies, to avert the evil by the processes of education, the remedy to be applied is more speech, not enforced silence.” - Justice Louis D. Brandeis