The terrorists arrested in Sydney and Melbourne are not religeous, they are criminals seeking personal gain from crime, in this case followers who will give them money to support a cause claimed to be a form of the religion. They seek power and wealth.
BTW I am not a religeous, I am an atheist but if people want to prey to somebody or something who am to argue, I just think it is a waste of time. Time that could be spent being a great human being - not claiming that I am.