The man's release comes a little over a week after he posted two short videos on his Facebook page in which he said a prison riot was endangering his life.
The two leaders met at the demilitarized zone on the Korean border.
"Some Western observers have been happy to turn a blind eye," said Jane Kinninmont, deputy head of the Middle East and North Africa program at Chatham House, a London think tank.
The official tally won't come till Saturday, but two major exit polls suggest that Ireland is moving away from its conservative Roman Catholic roots.
"The opportunity is not lost. It is just delayed," one U.S. general said. "It may have been too early to celebrate. It is also too early to quit."