[bandushrew]

The extremes always vote, many moderates only bother to vote if you can convince them the other side are totally insane/evil/stupid and life as they know it is going to be over if the other side get into/remain in power.

So politicians in particular get very good at making the other side look extremely insane, evil and stupid.

The better they are at that (lying) the better they do in elections.

So...the politicians who would be good for us tend to have integrity and strong personal beliefs about lying, and so tend to do poorly in elections.

Which leaves us with everyone else.