They didn’t reveal the information, the former prisoners first shone light on it when they asked for compensation.
They only felt like they had to make amends once the story came out, not during the 30 years prior. strange how that goes
Take control of the narrative.
Pay a research group to confirm what has already been revealed. On the wikipedia page it almost seems like the whole thing was their idea
(from a quick search this was revealed in 2011 by a german media, opening Stasi files)
And it works too
Escape Velocity Nova