An article by Prof. Noah Feldman makes the exact same point that the Korean has made previously, although the Korean was speaking of Afghanistan:

In 1953, after the armistice ending the Korean War, South Korea lay in ruins. President Eisenhower was eager to put an end to hostilities that had left his predecessor deeply unpopular, and the war ended in an uneasy stalemate. But the United States had a strong interest in regional stability, and some worrisome enemies to keep in check. So Eisenhower decided to leave tens of thousands of troops behind, and signed a treaty with the U.S.-backed government to formalize their presence. Thirty-five years later, South Korea emerged as a stable democracy.

The situation in Iraq today bears some intriguing similarities.

...

South Korea again provides an instructive example. The U.S. left troops in the peninsula after the armistice not to benefit the Korean people, but because it did not trust either North Korea or China. Like Iraq, South Korea had no meaningful history of electoral self-government. Indeed, for the first generation after the war, South Korea was governed by a succession of military dictators—and the U.S. acquiesced, even acting in concert with the governments. No one would have predicted at the time that South Korea—war-torn like Iraq, and in dire need of reconstruction—was a candidate for successful democratization.

A Very Long Engagement [Wall Street Journal]