So which set of laws are you going to choose to enforce?
Neither. US laws aren't applicable to North Korea, and North Korean laws aren't applicable here. I'm arguing that the correct moral and ethical standard is that we are not liable for what other people say. If Sony did something wrong, that's on Sony, not the U.S. government or the U.S. people. Do you feel compelled to apologize for me holding an opinion you disagree with? You shouldn't. You're not responsible for what I say, any more than the U.S. government is responsible for what Sony says, which by the way they only "say" in a work of ficiton, that happens to be a comedy.
it would stand to reason that the diplomatic solution would be the most rational of actions.
No, that reinforces the false notion that the government is responsible for things its private citizens say. That may be difficult for a dictatorship to understand, but it's the truth. Just go take a look at all the people on the planet who have at one time or another chanted "death to America", and notice how very many of them we've attacked for it. That would be, what, none? I suspect if the roles were reversed, our response would be something between total indifference and "That's tacky."
The diplomatic solution is to say what's true. Whatever it is in the movie you guys are ticked about, we didn't say. Apologizing for what other people do has always seemed like nothing more than a meaningless statement to me.