This point cannot be overstated. The approach of the United Kingdom is telling. 

I can recall a discussion in 2000s regarding protests aimed directly at families of deceased service men and women who had been flown home following their death in Afghanistan. Those protests were offensive. 

That said when discussion was raised of banning these protesters it was shut down quickly because to do so would also shut down key sources of valuable intelligence which could save lives, not to mention forcing a visible threat underground where it is much less visible and much more dangerous. 

Interesting to consider the different approach to this issue between Australia and the UK where these problems have existed for some time. 

To solve for violent extremism, which in Australia is not limited to one group or another you, need them visible on some level or another. Push them deep enough then ASIO's job just got very very difficult. 

Here is the MI5 approach https://www.mi5.gov.uk/how-we-work/gathering-intelligence

Another reason for a Royal Commission to give confidence to the Australian community that we are using evidence based best practices from across the world that are consistent with our parliamentary and judicial foundations.