> Isn't the whole point of democracy "a large enough volume of ignorance will average out to something sensible"?

No, which is why the avdocates of liberal democracy from the very beginning have also argued that an an informed populace is critical to it.

It is the point that “self interest averaged out over the whole population equals public interest”, though, but greed and ignorance aren't the same thing.

No, it isn’t. The hope is that the ignorance averages out and the informed and motivated voters are the decisive factors. In practice democracy works better than if that model was correct because while voters have preferences that they will happily profess that reliably lead to bad outcomes they reliably vote out parties that are in power when things go badly. Politicians have an incentive to do things that will get them re-elected so gross economic mismanagement is not the order of the day, mostly.

> they reliably vote out parties that are in power when things go badly.

That's not at all the case, and even to the extent it is it is frustrated in separation of powers systems like the US, where the faction voted out will often be the one least responsible for the problems, since three are multiple factions in power at any given time a day the ignorance leads to blaming the wrong one.

What I wrote was too strong, you’re right. If there’s a huge fuckup the part[y|ies] in power are very likely to be voted out, the smaller the mess the less likely they are to be voted out, and that’s complicated by the tendency to want to throw the bums out when the incumbent government has been in power a long time. I agree entirely that fixed legislative terms and term limits are stupid ideas, along with separating the legislature and the executive. Parliamentary systems are better than presidential ones.

>Isn't the whole point of democracy "a large enough volume of ignorance will average out to something sensible"? :P

I hope not. A much stronger argument is that government should be by consent of its citizens. Otherwise, you get democracy-is-bad-because-people-vote-wrongly arguments (e.g. women vote too left-wing or white people vote too right-wing).