This was a Republican governor asking for a tax increase that was actually a tax cut for lower and middle class voters. He went against his own party. His Republican opponents tapped into the distrust that the voters feel for politicians and tax hikes, by convincing people to vote against the tax cut. So poor voters basically voted to pay higher taxes, because they didn't want to pay higher taxes.
I admit that there's a first reaction of just complete impatience against all the reflexive voters out there that do what seems to be an extraordinarily stupid thing. They think they're being smart, and they end up hurting themselves.
But you have to look past that. There's got to be something deeper. I just can't imagine that such a huge percentage of the voting population was smart enough to know about the issue, smart enough to vote, and then stupid enough to vote the wrong way. It has to be something else. I'm just not sure where to look.
Unrelated topic: I came across something you might enjoy. Yes, there have been three-thousand-hundred-dozen Mac Switch parodies, but this one is pretty clever. I also sent it to Pee-tah.
http://www.waveworks.net/mac.html