Reddit mentions of The Left-Hander Syndrome: The Causes and Consequences of Left-Handedness

Actually the opposite is true, according to research documented in this book.

One study showed lefties were more prone to raising their right hand in surprised defensive posture, whereas right handed folks raised their left. In a driving emergency, this would mean that the right handed majority would have a greater tendency to veer onto the shoulder / ditch in right-hand driving countries, as opposed to oncoming traffic. The study's author predicted one would see higher traffic-related mortality rates in countries like England that drive on the left, and indeed that was the case at the time they posed the question.

If OP or anyone else is interest in further reading on the subject of handedness, particularly left handedness, I would recommend a book called The Left-Handed Syndrome by Stanley Coren, a psychologist and neuropsychological researcher. It's an excellent read.

Well, some have pushed for a “left-hander’s syndrome” condition to explain away things over the last few decades.

As relating to this particular case, if the “homework” that was found in Danville is in fact J. J.’s, then he claims that the rage in his heart first began because his sixth grade teacher forced him to write lines over and over as a form of punishment—something particularly painful for left-handers to do due to the way that they write. In short, being raised in a harsh right-hander’s world oppressed him so much that he eventually was driven to murder.