The article you linked to doesn't have any references, and sounds like it is based on an extremely poor translation. Looking at the official DPRK news agency, they don't seem to mention it: http://www.kcna.kp/kcna.user.a...
What the do say is that if they were to retaliate it wouldn't be a terrorist attack on innocent movie-goers, it would be a military strike on the leadership. That seems to match what the badly translated CNN statement says, i.e. that they wouldn't attack some random corporation or civilians, they would attack the leadership who they hold responsible.
The entire narrative of the DPRK is based on this idea that the majority of Americans are innocent, if deluded, and should be freed from the control of their masters. Without going in to how close to the mark that might actually be, it's basically a reflection of the US narrative on regime change.
We are deluded. There isnt a shred of evidence tying the DPRK to this hacking and yet they get all the blame. The movie was filmed in Fall 2013, but there were no statements from the DPRK until June 2014. They really arent the kind of people to miss out on a threatening press release if given even the slightest opportunity. Their press bureau literally salivates a this kind of thing. They also rarely lie. Huge exaggerations? Sure. But not lies. So it seems reasonable they didnt hear about the movie until June when official announcements and trailers started coming out
Meanwhile, the hackers apparently got into Sony's systems over a year ago. They first asked for money, then only later started talking about The Interview and wanting it pulled. The broken english used in their communications is not consistent with a Korean speaker. DPRK citizens speaking english is pretty obvious- they only have a small number of schools which teach it, and without many native english speakers, the teachers are very consistent.
We need to back up a little and reask the question of who did it. The answer might be even more interesting that the line we are being fed.