Anders Breivik is an exception, even amongst the insane he is an exception, even if you regard him as being possessed by the devil, he is an exception, the devil's work is more subtle, generally.
It is only when an ordinary man, someone who is not a world leader or a known terrorist does something like this that one realises quite how fragile human society is.
What is truly amazing is that he is an exception.
The Catholic doctrine that mankind is wounded, fallen, suffers from concupiscience, is so different from the Protestant doctrine of utter corruption and total depravity.
We are all capable of doing what Breivik did, what is amazing is that we don't because we are not utterly corrupt and totally depraved.
The exception is of course the killing of the unborn.