In Rosen’s case, the alarm bells went off not because he reported that North Korea was about to conduct a nuclear-weapons test but because he reported that the CIA learned of this fact from a source inside North Korea. In other words, Rosen revealed that the CIA had a source inside North Korea. It’s unclear whether the source was a human spy or a communications intercept; it’s also irrelevant because, thanks to this story, the source is probably no longer alive or active.
I’m not saying that Rosen should have been treated like a criminal; even Holder is backpedaling from that claim now. But he could have written his story without revealing that nugget about the inside source. The story might have been a little less compelling; his audience might have wondered how he or his official contacts knew that a test was coming. But the U.S. government might also still have a decent intelligence source inside North Korea..
It may seem odd for someone who has been reporting on national security matters for a few decades to say this, but just because the government is doing something in secret—and just because a leaker tells someone like me about it—that doesn’t necessarily mean it should see the light of day. That is especially so if the secret activity in question doesn’t break laws, expose deceit, kill people, violate basic decency, or … (feel free to add to this list).