That's exactly the same argument I used to justify why MtGox wouldn't shut down, almost word for word. It's the same argument I used to convince myself why they wouldn't shut down. They still shut down.
They're not anonymous, and they would run a real risk of bodily harm by such a public crime.
So we're relying on mob justice? Also, Mr. Karpeles hasn't been harmed and probably won't be.
(No, I don't want to see harm come to him, and I don't mean that comment above as a threat. What I do know is that there's a very strong chance that at last some of the BTC he lost/stole/squandered/etc. was owned by people who don't settle things with a lawsuit and a lawyer. Maybe it is unlikely, but it's something that I would be concerned of, if I was in his shoes right now)
I'm not saying we should rely on mob justice. I'm saying that the risk of reprisal is a perfectly understandable reason not to commit certain crimes. These guys are public figures and would be easy targets for people who want to harrass or harm them, unlike for example a mask-wearing bank robber whom nobody can identify and who stole only the bank's money.
These guys are known — like the guys at Mt Gox. They're not anonymous, and they would run a real risk of bodily harm by such a public crime.