“Thwarted lives have the most character-conditioned hate… The easiest idea to sell someone is that they are better than someone else. The appeal of the Ku Klux Klan and racist agitators rests on this type of salesmanship,” wrote psychologist Gordon Allport in 1958. His warning from more than 60 years ago came true again in modern-day America on May 14. On that day, a young white gunman named Payton Gendron—motivated by what the killer himself listed as white supremacy, antisemitism and fascism—opened fire at a supermarket in an African-American community in Buffalo, NY, killing 10 people and raising once again...