@Theages,
Perhaps I'm wrong, but I can see a link between the quote I enquired about, and the paradox of the Human Shadow.
In Jungian/Analytical psychology, the aspects of ourselves that we deny and repress, through the process of acculturation and other introjections, are put into our Shadow. The Shadow contains both positive and negative qualities, but is generally seen as negative by our Ego, because its contents doesn't fit with who we think we are and who we want to be seen as. The paradox is basically that these aspects are generally seen as 'bad' but they are great sources of strength and so need to be integrated back into concious awareness.
Although not exactly identical, I can see a link between N's view of evil and Jung's views. Breaking rules, or 'evil', is seen as a source of strength by both.
I apologise because I feel I am over-simplifying things; however, I am a newbie and we all have to start somewhere.
I'm enjoying reading other people's views, and learning from it at the same time.
Thanks