Because we have been living in this country,and we have never made our voice heard at the national level.
VOA: standard.2009.11.27
That gave them boldness that gave them an incredible spirit to go out and talk about something that had neverbeenheard of, neverbeen preached of before, all across the known world.
Every other character on the show who has left Don Draper's ad agency has either neverbeenheard from again, or revisited in a one-off episode and then rarely to neverheard from again.