By this logic isn’t HN an echo chamber or safe space? It’s heavily moderated, to the point where only certain topics are even allowed to be posted (ie community is exposed). For example I can’t post my ballet gossip on hacker news, it would be considered off topic. I could argue hacker news is an echo chamber that doesnt allow for the ballet community relevant interests.

Well, there is line to be drawn between echo chamber and just keeping community on topic and it can be blurry one.

For example I wouldn't consider rule "no politics talk" to be echo chamber on any social space but banning/shadowbanning one kind of leaning vs the other would certainly lean to that.

Then again it is not as simple as some topics just produce people that cannot actually hold conversation about what they talk about and are more interested in throwing their piece and not trying to honestly discuss anything. The unkind extremisms can be banned without turning community into echo chamber even tho technically kicking the <person> having <view> would fall upon "banning one side of politics"

Or on the other side, would you consider post discussing BDSM kinks of some ballet person to be on-topic and belonging to ballet community ? Or who they gave money for political stuff ? Would those comments improve that community or just be off-topic waste of page space ?

I’m not the person arguing against echo chambers. I actually am completely fine with echo chambers because people can freely move between them if they want. I can go watch cats and I can go watch ballet and I can go have significant discussion on a technical topic and it doesn’t have to happen all in one feed.