The latest American mass-murderer – Christopher Harper-Mercer, who gunned down nine people and injured nine more, two critically, at Umpqua Community College in Roseberg, Ore. Oct. 1 – is also the latest example in what I call the literature of rejection, someone with a disproportionate rage at life’s inequities and disappointments who decides to take it out on others. The cast of characters includes mass murderers (Timothy McVeigh, Osama bin Laden), dictators (Adolf Hitler) and assassins (John Wilkes Booth, Lee Harvey Oswald).

In Harper-Mercer’s case, he had been rejected by a firearms’ academy – too immature and entitled, what a surprise – and he didn’t have a girlfriend. This would be laughable if it weren’t so deadly. ...