If you had read the Wikipedia article you quoted more thoroughly, you'd know that Angela Merkel only joined said left-wing movement (the Freie Deutsche Jugeng, which was more or less the marxist-leninist equivalent of the Hitlerian Youths) because, while membership wasn't mandatory, not volunteering to be a part of it made it difficult to access higher education.
In fact, while she was completing her studies, she was denied a position
Hell, Stasi had on file her "political and ideological deviations" from communism and the GDR, and her support of Solidarność (not to mention that she's been part of the christian-democratic movement from the very start of her political career after the reunification, so you'd be hardly pressed to call her a "left-wing activist").
The point is that yes, it was possible to live well in East Germany, provided you toed the party line. Drawing any kind of negative attention from the German version of Big Brother however could (and, more often than not, would) land you in a world of shit.