I assume our government knows of these camps and has (at a minimum) satellite photos of them. Why does it take a Japanese TV network to tell us about this? I can't see what anyone could have hoped to gain by keeping this a secret. The more the world knows of this, the better.
The NK's have had camps like these since the 1950's.
President Bush has seen the KH11 and KH12 satellite photos of the camps (so did Clinton). He further has received intelligenc reports of eyewitnesses. As a result, he "loathes" that little dictator, Kim Jong il, and told Woodward just as much. Well, it is common knowledge in Asia (particularly Seoul and Tokyo).
In fairness to Bush, he was much more morally outraged than Clinton could ever be on this, but unfortunately he has his mouth full with one big Iraqi Burger right now. Once that is chomped down and digested, I am pretty sure the effort to liberate North Korea and free the camp inmates, will begin in earnest.