When Elon Musk took over Twitter, he prompted a mass exodus of advertisers worried his reign might elevate hate speech and other stomach-churning content that would then appear alongside their ads. Musk had said he would restore a vast swath of accounts banned for violating Twitter policies, and he did, resurrecting nearly 12,000 accounts, including violent neo-Nazis. Well, the advertising industry’s worst fears have come true. Twitter has placed promotions for major advertisers including Amazon, Snap, Uber, and the US Department of Health and Human Services on the profiles of prominent white nationalists, according to a report in the Washington...