That's the motive ascribed to him by the DPRK, a confession they extracted while he was detained. They routinely extract false confessions of "plots to overthro

That's the motive ascribed to him by the DPRK, a confession they extracted while he was detained. They routinely extract false confessions of "plots to overthrow the state" and the like. So this confession is worthless. We probably can't know what he actually did, or why he did it. The incident could even be made from whole cloth.