Numerous articles say otherwise, even wikipedia says this:
South Korea
Pornographic websites, books, writings, films, magazines, photographs or other materials of a pornographic nature are illegal in South Korea, although the law is not regularly enforced. Distribution of pornography can result in a fine or a two-year prison sentence. Since 2009, pornographic websites have been blocked by the South Korean government
And its the distribution/producing part that would actually be the most risky, especially receiving money for it. So everything does point out to him vanishing because of it.