Safety Concerns and Cancel Culture
The City of Melbourne cancelled Helen Joyce's speaking event at short notice citing vague and unspecified safety concerns from potential disrupters - presumably the usual, male trans activists.
But it's the jobs of the police to ensure people can exercise their rights to freedom of assembly and freedom of speech instead of bowing down to these threats of public disorder.
Similar tactics were used by trans activists at the National Library of Scotland to get 'The Women Won't Wheesht' banned from the library's centenary exhibition.

