This is a question that, living in the good ol' US of A, I ask myself regularly during elections. I asked it several times a day while Dubya enjoyed his eight year reign. It has particular saliency now as the current health care "debate" rages, literally.
Universal health care is a no-brainer. Full stop. Yet the people who have the most to gain from a public health care plan show up at Town Halls apoplectic with fury and brandishing signs reading "Keep your government hands off my Medicare" (Medicare being the government funded health care option for the elderly and disabled poor).
Finally, the BBC is offering an answer.