Apparently, the American swing voter tends to think, “If I’m going to get screwed over, I want it to be by someone who is aggressive as possible about it.”
I think it's slightly more rational than this. I think such voters are paranoid that "their money" is going to be taken from them and given to someone else, most likely someone "undeserving," and that they will personally get nothing. If they vote for Democrats there's a chance they'll get some goodies, but also a chance the goodies will go to someone else. If they vote for Republicans, they think (rightly or wrongly) that at least their taxes won't go up.
It's why the general pain caucus approach of decreasing government benefits for the middle class has been so bad for Democrats. It's made people perceive all government benefits as stuff for the poor, as welfare.