Terror attacks go back along way, decades before 9/11, Entebbe, Munich etc but they all have their twisted roots in a lack of a Palestinian homeland, combined with a centuries old hatred of the Jews, Holocaust denial & the actions of the Israeli state.
Then there is ISIS, with a far right Islamic ideology (those that care for one) who want to kill anyone.
On Gaza, didn't the Israeli Govt fund and support Hamas? as a counter to the PLO.
For me, the people marching aren't the issue, we can see them, they can be be looked at, its the ones we don't see, the ones on the dark web, returning ISIS fighters, people let in on Visa's.
We are often told that Australia has the correct immigration policies that we should follow, events show, thats no guarantee.