Hackers move easily between different levels of abstraction and believe that things in general can and should be understood. They try to never stop asking 'why?' and this leads them to find places where the system is incongruent. Many of these realizations are benign or even progress the system, and the advantage gained just helps the hacker succeed within it (eg. pg's main use of the word hacker). But some realizations contradict a foundation of the system (like insecurities of its central nervous system!).

The system is built on abstractions, takes them for granted, and reacts extremely harshly when they are broken (for this is an existential threat). The system can only understand a broken abstraction in terms of the abstraction itself, rather than in terms of underlying reality. Hence we end up with phony blame-shifting terms like "identity theft" instead of reality-based "fraud". Meanwhile, hackers see the failure of the abstraction in terms of the underlying reality and have a hard time seeing what the big deal is - just reprogram the abstraction!

Most people's thoughts are contained mostly within the system, having been indoctrinated into it from birth (constant rote memorization in primary school, blind repetition of contradictory facts, scolded by adults with tenuous justifications every time they don't follow the pack, etc). So they take what they're told at face value and follow along, all the while never seeing the whole picture and hence remaining afraid of mysterious agents that can take advantage of them for what they don't understand. If they're told that a collection of email addresses is a threat to their way of life, they'll actually believe this because they lack the broad framework to analyze the truth of this statement. They'll instead trust the system and assume it's correct, feeling that if it were indeed wrong they would no longer be able to take anything for granted.