> "Oh, all the computers are already on? That only happens when Washington's waiting on something. Oh well, I'll carry on like this was any other low-risk morning"
Because those situations were also low-risk mornings. He only saw that pattern when people left late. He had no reason to expect that people would be working early in the morning because that situation had never occurred. Further, a secretary playing a computer game in the morning suggests business as usual, no one working.
> He was in a perceived low-risk window. ... because he was negligent
No, someone else set up the computers and software with F6 and F7 command functions side by side and then evaluated the entire network as low-risk for interns under all situations. It is perfectly reasonable for an intern to take the same low-risk perspective as his superiors.
> Same reason why "rm -rf " is the one keystroke away from disaster. Perceived risk has nothing to do with it.
Perceived risk has everything to do with it. It is inconceivable today that an intern would have unrestricted access to a company's file system and be literally a few keystrokes from disaster. The key reason for that is because perceived risk now is much closer to actual risk. In 1983, no one had a clue about the kinds of things that could go wrong. Understanding real risk is a painstaking process requiring time, trial and error.