I dunno, I have got a fair amount of imaginary internet points on here before for suggesting that there is a good chance that Snowden is still working for the NSA, which isn't exactly the popular opinion.
edit - well ok, 4 :) but it didn't get hammered down
Indeed, I got -40 karma on this story. Dissenting opinions are not tolerated on NSA stories.
Therefore people who do not agree with the HN consensus "self-censor", and a vicious circle is created, with only a single narrative displayed.