I'm glad you pointed out the definition of 'terrorism'. Those particular words were well thought out, I believe.
How much real fear in instilled in you, the Australian people, the Australian government, or the target site's admins as a result of this event? Any fear at all? Is this fear a reasonable response to this event? It's just computer systems and public websites, after all. Do you equate 'inconvenience' with 'danger'?
We're being conditioned to experience fear when we're told, on demand. We're told that an attack against a server is an attack on the people and therefore the expected response is fear, nee 'Terror'. As an individual, I ask you if you choose what you are afraid of? Do you hold in yourself the determination behind your actions, your beliefs, and your responses to external events? Do events out of your control cause you to fear them and their instigators because you believe that you are truly in danger, or because you have been conditioned to respond as if it were so by people who have a specific interest and benefit by your fearful response?
If you want to call these events 'Acts of Terrorism', if you want to be afraid, please do so on your own terms and not those handed to you along with the blindfold and handcuffs. You are a powerful individual, my friend, and you are capable of deciding for yourself what is right if you will only objectively view the events and effects that you experience. Keep that power to yourself, instead of simply handing it off to those who would manipulate you for their gain.
Happiness is twin floppies.