I have never seen anything like this. The storyline of blaming Sarah Palin/Rush Limbaugh/Glenn Beck/the tea party/the right continues even though there is NO EVIDENCE SUPPORTING IT.
I remember the movie Taxi Driver being blamed for John Hinckley's assassination attempt on Ronald Reagan.
I remember heavy metal music being blamed for teen suicides.
I remember "gangsta rap" being blamed for all kinds of violence. (see)
I remember Dungeons and Dragons being blamed for a whole bunch of murders and suicides.
I remember Beavis and Butthead being blamed for kids starting fires. (see)
I remember sex-ed classes being blamed for teen pregnancies.
I remember Bill Clinton being blamed for teen blowjobs.
More recently, I remember video games being blamed for the Virginia Tech massacre.
(see: Dr. Phil Suggests Video Games to Blame for Virginia Tech Shootings)
I remember South Park being blamed for a redheaded kid getting beat up at school. (see)
I remember the show Jackass being blamed for a kid setting himself on fire.
So if you want to make the point that it's not fair to blame Sarah Palin, yeah you probably have a point. As far as we know, the shooter was not motivated by her or by any other political figure (although we don't yet know much about him, he may well turn out to be a teabagger, who knows)? But don't pretend like this is some unprecedented phenomenon. Especially when we remember headlines like these: