It's one of the most frustrating truths we have to deal with. Why do so many people vote against their own self interests? It's borne out in the fact that the reddest of states, especially in the south, are predictably republican in spite of the fact that they are also the poorest economically and also are on the receiving end of the most government benefits.
Gary Younge in The Guardian, UK does an excellent job of tackling this most frustrating of issues in Working class voters: Why America's poor are willing to vote republican
There is nothing more vexing to liberals than poor Republicans. Their very existence rankles. It turns their world on its head and their assumptions inside out. The effort to explain them is understood not just as a political paradox but a psychological disorder. They have been duped. They must have been. How else would one explain putting your cross next to the man who derided them as "victims" among the 47% "I don't worry about". To many liberals these are turkeys voting for Christmas or lemmings off for a leap; the condemned tying the noose for their own execution.
One of the most familiar clarion calls of the tea party patriots has been
"Get government out of my Medicare!"
At times the contradictions are striking. In August 2009, when opponents of Obamacare were disrupting town hall meetings with claims of death panels, Kenneth Gladney and other members of St Louis tea party got into a fight with Democrats at a public meeting. He had to go to the emergency room with injuries to his knee, back, elbow, shoulder and face and ended up in a wheelchair. It turned out Gladney, who had recently been laid off, had no health insurance. He appealed for donations.
[...]
"For decades, Americans have experienced a populist uprising that only benefits the people it is supposed to be targeting," writes Thomas Frank in What's the Matter With Kansas. "The angry workers, mighty in their numbers, are marching irresistibly against the arrogant. They are shaking their fists at the sons of privilege. They are laughing at the dainty affectations of the Leawoof toffs. They are massing at the gates of Mission Hills, hoisting the black flag, and while the millionaires tremble in their mansions, they are bellowing out their terrifying demands. 'We are here,' they scream, 'to cut your taxes."
Poor and lower middle class republicans voting against their own interests is not as simple as it seems on the surface. Yet the reasons include everything we imagined and more. I urge you to read the article.