There was Chiara de Blasio, the 19-year-old daughter of New York’s next mayor, gently baring her battles with depression, alcohol and drugs in a day-before-Christmas YouTube video. The sincerity and eloquence she showed were guaranteed to touch the hearts of many New Yorkers. And her message could well inspire countless young people in similar situations to seek help, as she urged them to do at the end. But Chiara’s startling video, coming eight days before the official start of the Bill de Blasio era, also left you with an eerie sense of being manipulated emotionally.