Because her privacy matters a great deal to us. This is not just any ordinary person and it would harm rather than help if this blew up in the media.
> You say she was completely innocent, then why hide the story?
Because even people that are innocent are not always benefiting from having their plight spread out for all the world to see.
> We all at HN, have no idea what the case is.
No, you are wrong in that. There are a few HN'ers that know the real identity and some of the details behind this (pg for one). And I'm pretty sure they'd agree that keeping her identity a secret is of paramount importance with respect to her safety.
> So how can you expect help in such circumstances?
Well, I gambled (rightly it appears) that HN would be capable of judging for itself whether or not we were sincere in our appeal for help and that we had weighed properly the decision to keep her identity a secret.
> We all can make a much bigger difference, if we know the true story behind.
No, you could not. It would satisfy some curious people but it would not make a material difference. If this situation is not resolved in a positive way in short order and with the main protagonists' permission we may still have to do this, but if and when that happens it means we have lost the current battle.
> Get the story to the Front Page, someone will push to the right person and the media will act fast.
It may come to that yet. Better hope with us that it will not come to that.