The baffling (to liberals) fact that a large minority of working-class white people vote for conservative candidates is explained by psychological dispositions that override their narrow economic interests.
My hypothesis would be: religion; distrust of large government; white self-interest. Even if that gets the explanation a bit wrong, it shouldn't be "baffling" or require an appeal to personality types.
It's almost more interesting to ask, what sort of person does find the existence of working-class conservatism baffling? I'm going to guess and say there are at least two types, "naive people" and "activist believers". The naive ones are those who don't understand it because they are genuinely clueless about something, e.g. that schemes of economic "redistribution" are themselves an opportunity for favoritism. I think of the "activist believers" as people who do know reality (whether or not they are working-class themselves) but who for specific reasons think it's politically obvious that left is better than right for the working class. Perhaps activism is not the best label here, given the word's frequent connotation of flakiness, fanaticism, and chosen involvement in a cause. I'm thinking more of organized collective self-interest - the people who lead, and the people who participate.
In fact, it strikes me that the perception of politics as nothing but the expression of mindless tribal affiliation is itself an intellectual blind spot, present in LW's circle of ideas but also in many other places (and once again, one could ask the sociological question, who has this blind spot and why). Politics is also about alliances and negotiations, it's about your group having a seat at the table when decisions that affect its future are made. Even a household or a relationship can have a "politics".
And even a politics that expresses nothing but tribal self-interest doesn't have to be mindless. I see an "altruist" or "universalist" bias here, which assumes that politics is fundamentally about working out what's best for everyone, as opposed to just working out what's best for your tribe in a large and often hostile world, where there are powers from outside the tribe who also have political representatives.
The caricature in the US:
The left would like to fleece the rich in favor of the poor, but the rich are hard to fleece: are politically organized, have influence in government, can lobby, can hide money, etc. So in practice they do the next best thing: fleece the middle class in favor of the poor: that's where a lot of money is too, and it's easier to get it. That some working middle class types aren't fond of this should surprise no one.
There are cultural issues in the south, too.
I don't think voting patterns are that weird, I think the puzzlement here...
An article from the Wall Street Journal. The original title might be slightly mind-killing for some people, but I found it moderately interesting especially considering that many LessWrongers formed part of the data set for the study the article talks about and a large fraction of us identified as libertarian on the last survey.
Inside the Cold, Calculating Libertarian Mind
The original paper.
Understanding Libertarian Morality: The Psychological Roots of an Individualist Ideology