Contradictions of South Korean military supremacy

The South Koreans think they could thrash the North Koreans when there is a military conflict. They keep saying that they will respond with punitive measures. And because of their superior armed forces, they took liberty to conduct war games, simulating an attack on North Korea in the islands closest to the North. The Yeonpyeong is only 7 miles or 12 km from the North Korean coast.

Why is there