One problem I have with the "you don't see what I see, just trust I'm right" line is that there's no way to refute it -- short of an outside, independent party providing a different compelling analysis and interpretation of the forensic evidence. The relevant parties (Sony, FBI, etc...) don't have any interested in sharing, and in fact have a vested interest in not sharing, that forensic evidence. So... I strongly suspect that right or wrong, the existing given position is the story that will always stand.
The title of the Engadget story is wrong, the FBI did not explain anything, and then saying "they don't see what I see." is fairly idiotic way of adding to the explaination.