Fourteen years ago, at a human rights conference in Oslo, I met Julian Assange. From the moment I encountered the wraithlike WikiLeaks founder, I sensed that he might be a morally dubious character. My suspicions were confirmed upon witnessing his speech at the conference, in which he listed Israel alongside Iran and China as part of a “rogue’s gallery of states” and compared the Guantánamo Bay detention facility to a Nazi concentration camp. Nothing Mr. Assange has said or done in the intervening 14 years has altered my initial impression of him as a man unhealthily preoccupied with the shortcomings...