How come vegetable and mineral oil don't short circuit computers?

I saw this video and read some articles, and I'm wondering why these computers don't short circuit.

http://youtube.com/watch?v=PtufuXLvOok

How come vegetable and mineral oil don't short circuit computers?internet security 2006

Maybe be they are non-conductive?

How come vegetable and mineral oil don't short circuit computers?microsoft

Because vegetable oil does not conduct electricity.