If I had enough money I would definitely be building weird shit which could include tunnels. I already like caves. I don't particularly care about DPRK, but I'm sure normals would find something wanting in my motivations.

The problem is not that he built some tunnels. The problem is that he lethally endangered his employee. Rich people make tasteless decisions all the time (for proof, drive through any tony suburb). It is important that their tastelessness not be negligent.