His action is controversial among netizens. Some say he is right to go to battle field for the sake of the people in need, others are opposite because he violated the law. Actually, his travel was not allowed by Korean authorities, which banned publicly any Korean nationals t volunteer to battle field as a fighter. Korean government even threatened to jail him after getting back to Korea.
I'm more of a supporter of him even though his action is illegal. I don't think it is right thing to limit personal choices for the people who behave for a good cause. More over his action does not harm anyone.