>there's a total shutdown of public discourse as most people won't go on record to say anything that might not be consistent with the party line.
>...driving anyone with a deviant opinion behind closed doors. Soon enough, everyone is screaming into an echo chamber.
Funny, I've always thought downvotes on HN encouraged the same, albeit to a lesser degree. It's one thing to use downvotes as a moderation tool, submerging comments from others with whom you don't agree. It's another thing to "penalize" (FWIW) a person because you disagree with him/her. That it seems acceptable is a smaller symptom of the bigger problem.
Reminds me of the Black Mirror episode #1 this season.