The article itself was a bit disappointing because it focused on political issues. In my opinion the strength of HN in this regard is that it is both a "sjw cesspool" and a "haven for alt-right", as evidenced by the fact that a comment on a controversial topic can easily float near zero points while raking in both upvotes and downvotes. And even those who refer to it as "the orange site" still come back and comment. In other words, HN may be an echo chamber but it is a pretty big one with a lot of voices in it.
The echo chamber effect on HN is far worse than any comparable site, it's just not as obvious because there's zero transparency.
At least there are tons of 3rd party sites that allow us to see censorship in real time on Reddit. No such thing exists for HN.
I have no sympathy for the moderators here. I believe they moderate very arbitrarily and are accountable to no one.