Speech?
Regardless of any stance here on the matter the Australian Government isn't asking to censor any speech .. they want to dampen down the glorification of violent acts by asking social media to not carry the video of the stabbing.
You can write paragraphs about the event, transcribe what was said, the speech part isn't being asked to be censored here.
On the second point, coordinated five eyes actions requiring oversight from citizens of all countries involved and being kept in check is one thing; using the statements of Senator Jacqui Lambie (a fringe member of a finge political party (Clive Palmer, the Vogon offspring of Jabba the Hutt)) as representitive of Australian policy makes as much sense as taking Senator Ted Cruz a spokesperson for the USofA.
Pragmatically spies and cops might want encryption with backdoors, practically they're unlikely to get this .. "even in Australia".