Times have changed.
The facts are that Australia is doing nothing more than any other country would do, or would be expected to do, in similar circumstances of being host to twenty one World leaders.
Get over it, get used to it!
Fifty years ago the then PM, Sir Robert Menzies put the Army on the Australian wharves, in a non aggressive role. I have a recollection there are constitutional reasons that the Australian ADF can not be deployed within Australia, in an aggressive role?