Freaknik started as a picnic but it eventually morphed into a raucous gathering of thousands of young people, a history highlighted in the new Hulu documentary “Freaknik: The Wildest Party Never Told.” But there’s another part of the story that hasn’t been widely told — the behind-the-scenes tension between Black political leaders in the city around the event, and the role a storied civil rights organization played in trying to calm Freaknik down.