It was my first reaction at seeing the headline. I suspect they skewed the number to make it sound more realistic
Because it already happened: http://www.theregister.co.uk/2008/11/19/hospital_computer_virus_shutdown_update/
Not one person, definitely. Of course there have always been people who pushed it for their own gain, but they largely grew from the collective myths of the people. That seems sanest to me, anyway.