With any group of people in life, sad things happen, and crazy things, and happy things. When you're in the public eye, it's just amplified, that's all.
There is something that is much more scarce, something rarer than ability. It is the ability to recognize ability.
If we take as given that critical infrastructures are vulnerable to a cyber terrorist attack, then the question becomes whether there are actors with the capability and motivation to carry out such an operation.