Federal officers killed 37-year-old ICU nurse Alex Pretti in Minnesota early on Jan. 25, and that same afternoon, Bruce Springsteen sat down in Colts Neck, New Jersey and wrote a furious response, “Streets of Minneapolis.” He recorded the song the next day, got it out to the world almost instantly, and was onstage in Minneapolis performing it with Tom Morello by the end of the week. He wasn’t alone, either. Just as Springsteen’s song dropped, Billy Bragg released “City of Heroes,” and soon after, NOFX came out of retirement to drop “Minnesota Nazis,” reworking their earlier “Huntington Beach Nazis.” On...