Final answer:
Arthur's disbelief stems from the same incredulity that affected many during WWII, who found it hard to comprehend the industrial-scale atrocities of the Holocaust. Influential figures like U.S. Supreme Court Justice Felix Frankfurter struggled to believe credible eyewitness accounts, emphasizing the challenge of accepting such unprecedented horrors.
Step-by-step explanation:
Arthur's disbelief regarding the murder of young Jewish boys in the camps can be attributed to the overall incredulity of the Allies during World War II. Even after credible eyewitnesses like Polish resistance fighter Jan Karski reported the atrocities and mass executions, key figures like U.S. Supreme Court Justice Felix Frankfurter found it difficult to accept such horrific truths. This level of denial could be due to the seemingly unthinkable nature of the Holocaust, challenge in accepting that a civilized society like Germany could perpetrate such crimes against humanity, and a lack of precedent for such industrial-scale inhumanity.