This kind of terror attack only creates a greater divide in societies and causes fringe elements to become more vehement in what they say and do. Violence does not solve anything, it just scares people into either blind and insincere obedience or counterattack.
I realize also that this attack is not representative of Australians, just as the 2014 Sydney terror attack in the Lindt chocolate cafe was not representative of all Muslims in Australia. Lets criticize bad ideas without violence, it shows that we are morally superior than our opponents. We are morally superior to ISIS/Al-Queda/Boko Haram etc., but these bogans that carried out this attack are clearly not. The religion of Islam is never safe from criticism, but the people that believe in Islam should be safe from violence.