Anyone who would let a single individual have the keys to the kingdom and not insist on a system of checks and balances should be blamed and fired.
The rogue's manager simply did not do their job protecting the organization. In the old days the question always was "what happens if the systems guy gets hit by a bus?" Passwords are supposed to be in an envelope in the safe. Data Processing 101
Is this an isolated example, NO. As a consultant I know of several organizations, (no longer in business) that had this same problem. One CEO decided to fire the whole IT staff just before Christmas, forgetting to acquire the passwords and documentation first. Out of business...