You need limited liability or investment becomes a very risky prospect. Imagine investing to get a 10% stake in a startup company and they end up getting sued because they violate some patent accidentally?
The current situation all comes down to intent. The way it's supposed to work is that if someone was actually negligent in their duty, then, and only then, do they become personally liable.
You say the fact that it was stolen is irrelevant. Lets say someone ram raids the office, holds a gun to the CEOs head and demands the keys to the bitcoin. Do you think that he should be personally liable in that situation?
My point is that shit happens in business, debts can be created in unexpected ways and sometimes those debts can be far in excess of what was invested. It's not really reasonable to expect shareholders to be personally liable come what may.