So, ABC "broke" the story that the US is engaged in covert activity designed to topple the Iranian government. There's no actual new information other than the confirmation of what everybody has assumed - that we had a presidential finding directing the covert part of our official policy of trying to change the Iranian regime. The only thing this story does is help the Iranian government portray itself as a victim of American aggression (which it is, but American intelligence officers shouldn't be helping Iran by stupid leaks).
Other people are blaming ABC and Brian Ross (like here, here and here). I don't blame the media. Their job is not to act as another arm of American power through self-censorship or repeating the official line (although in general that is exactly what they do). To me, this story is an example of ABC trying to get a leg up on its competitors by getting a "scoop" however they can. ABC is simply another corporation trying to enhance its product.
Ironic that Blizzard Entertainment can keep a secret better than the U.S. government.