They have different citizenships, different cultural messages from birth, different access to such messages from the rest of the world (such as the US). They cannot accurately be described as having the same nationality.
Different something, sure.
But North Korea has more in common with South Korea than it has in common with any other country. And South Korea is probably much closer to North Korea than any other country is to North Korea. Anyway, this is all nitpicking, because ArisKatsaris' main point remains: South Korean leaders don't refrain from harem-kidnapping based on national character, but based on the negative incentives they face.
Here's the new thread for posting quotes, with the usual rules: