Perhaps I'm an old man but it seems really retarded for folks like this to be wasting time with a problem that had been solved over a decade ago. And it doesn't have to be exactly the same -- but something is better than anything. Also, the retail site Amazon has also had community review moderation for the better part of a decade.
Even if there's only a "like" button that brings more liked comments up, it'd be something. No system is perfect, but all of them work well enough to bring useful content up and push trollish content out or invisible. And if trolls want to fight amongst themselves, they can still do it (either at the bottom of the page or by turning their threshold off).
You simply cannot have folks pick and choose which comments to keep and which to censor. That definitely will not make for good discussion, as evidenced by their efforts to date.
And even if its wordpress, as someone pointed out its open source and I bet there are multiple plugins that setup such functionality. I simply don't believe that these "tech" people in Silicon Valley would have a problem finding someone to do a little coding for them. Seems lazy more than anything else.