That’s a dangerously naive position for them to hold. If Kim has even half of the amount of artillery along the DMZ trained in on Seoul that he is rumored to have, he can make a real mess out of that city in a very short time.
That’s a classic example of Normalcy Bias.
I would take the opposite position, and assume that in addition to all the artillery Kim allegedly has, there are also caves a bit further back from the DMZ that have several platoons of Stalin’s Organs hiding in them.
From what my friends relay South Korea sends food to NK. They pay their “peace fee.” They are not threatening South Korea. They are aiming their rockets at Japan and threatening us. They expect payment to not threaten or attack us.