Yes, citizens of every country deserve to have access to healthy and quick dining options. I do not know personally the situation in Korea (which Korean country is being discussed is totally unclear here) but my gut says that yes, there should be more healthy fast food places. North, South, or any Korea would benefit from these options.
Healthy fast food places are at an all time need because of all obesity issues in the world today. Healthy fast food places will decrease the obesity percentages drastically but obesity will never completely be stopped. The issue isn't just in Korea either. This needs to take effect in every country.
Yes, Koreans should have more options for healthy fast food restaurants. People are becoming increasingly overweight or obese around the world, partly because of the availability of fast food restaurants. Because people like the convenience of fast food, it is a good idea for healthy fast food restaurants to establish themselves in Korea and elsewhere, so people have better choices.
Koreans have more than enough healthy fast food places. But when it comes down to it it really is nobodies business but their own. Why would anyone care what Korea does? That's kind up the whole point of sovereignty; the ability to run the state as it sees fit without interference from anyone else.