You should read the source. The guy is a lib, but he very knowledgeable about Korean history. You can even see in the second paragraph that he directly counteracts the media portrayal of Jong Il. He is very fair throughout the book, and I would really encourage you to read the entire thing (it's not particularly long). A comrade posted a digital copy on the Discord if you search for the title. Not gonna forgive you until you read it ;)

But yes, I think the focus here is that we are talking about people in the Kim family's inner circle (though it is his illegitimate son) who are still required to have a permit. That stands out to me that they didn't get a special exemption. These sorts of policies are far from ideal, but when you have a country that is living on the brink of invasion by Western Imperialists for decades, you need to be regimented. The precariousness of their position as a country justifies the amount of authority they are using. The whole country is more or less militarized for good reason, and in the military you can't have your soldiers doing whatever they want, they need to request leave, and be back on time or else the unit could be weakened.