I think their hands are kind of tied. He's not a valuable asset, he is a fuckup. He doesn't hold the same value as a random citizen tourist that didn't have the intention of defecting. He's not in a position to provide valuable intel. They either kick him out or treat him like a god and let him go home to tell everyone how awesome North Korea is. Punishing him only hurts their image.
Odd that you put the doggy diddling in the headline but omit the child abuse