But, realistically, the power is there on any site featuring user contributions - Hacker News, Twitter, Slashdot, etc. etc. Humans are fallible; given infinite time, the same thing will happen on those sites too, and probably worse. If you push someone hard enough (I don't know the full story, but I believe the CEO was provoked) they will lash out and do something stupid unless they are incredibly serene or lack any emotion.
If that possibility is too much of a concern, maybe we need to come up with an alternative - like some kind of decentralised, mass-distributed reddit-like. Actually, wasn't that usenet? Is it too late to get that back?