Pretty much every time something like this happens they do condemn it and distance themselves from the act - as they have already done so today.the Islamic community themselves need to publicly distance themselves from these kinds of actions. Arcing up about white prejudice, when in fact it is proto-Islamic prejudice against "infidels" that causes these events in the first place, is simply not reasonable in this case. When Islamic militants declare war on the west and do THEIR best to make it an us-vs-them situation, what do you think the reaction is going to be? Of course people are going to make racial/ethnic/religious generalisations. The only realistic way to prevent/reduce that is for the Australian Islamic community to harshly reject this kind of behaviour, otherwise they will be seen, rightly or wrongly, as being complicit with it.
The media may not run to far with it though.