This sounds like a terrible movie with poor taste.
Granted that you don't like NK, but to make a movie about killing the NK leader isn't in good taste and is needlessly provocative.
If someone made a movie depicting Obama getting lynched while eating watermelon and fried chicken, there would be a lot of displeasure also.
NK is almost certainly behind the cyberattack, but it is going to be hard to prove a state actor was behind it and even harder to produce a measured response. Should you bomb people just because a private, non-US corporation gets into a tiff with a tin pot dictatorship? Remember, it is SONY's freedom of expression at stake here. Not Obama's right to make a speech criticizing North Korea. This is not an attack on the US Social Security's website or something hitting US citizens as a general category. It was an attack on Sony and Cronies, and as far as the info revealed showed, the Cronies weren't very attractive people anyway.
I don't like the Zimbabwean dictator Robert Mugabe, but if I used inappropriate language to describe him in the wrong situation (eg called him a N***** while at a Black Panthers fund raiser) I would almost certainly get my nose broken, freedom of speech be damned. If you were the public prosecutor, would you want to muster massive public resources into investigating this assault and battery incident and prosecute the Black Panthers for bashing me and denying my right to freedom of speech?
NK could have acted the generous, broad minded big hearted guy by ignoring the movie. Now the US should act the wise democracy and not muster the military/ CIA/ US public institutions to defend corporate interests.
Most bizarrely, these are Japanese corporate interests that the US wants to defend and even the right wing Japanese leader Shinzo Abe isn't defending Sony.