Hacktavism - All Together in the Vitual

This article about hacking is my first experience with hacking. The idea that programs could be developed to hack into high up places like NASA which has government programs and secrets. These programs could be detrimental to a government or a corporation, many files could be stolen or destroyed. With such a hash program hurting peoples files it would make it hard to replace them. I was quite confused when they were discussing how hacking was not burglary or theft, just because there is a trace of the hacker left behind unlike in burglary. I was confused how hacking was different then what I thought about hacking, I thought hacking was a way of destroying or something but they consider it something different. I didn't quite understand the view they took on hacking.