I don't think that poster was suggesting for one moment that the ten years those women spent locked up was good news.
She's commenting on the rescue and the particular news clip on this thread of the man who helped to rescue them, and that particular part of the story is good news, good that he and the other people overheard Amanda Berry, good that he decided to help rather than decide it was none of his business, good that he was able to get her out, give her his phone, wait with her until more help arrived and good that he then gave the police a description of the car that helped them capture the man who owned the house.
All of that is good news all around. I think you are being unfair to suggest she meant it was good news those women spent ten years locked away when it's obvious to everyone else, when she has actually clarified the point for you, that she's talking specifically about the rescue and the fact that the women are alive and now safe.