This might be a controversial take here: and let me say first up I think the dude deserves a posthumous award or statue or something for his bravery in standing up to tyranny.
But: this dude went over to Ukraine to fight a war. He was there to kill Russians, of course he should have been protected as a POW, BUT Its a bit fuckin late to start caring about treatment of POWs just suddenly because they killed one of ours. Where the hell was our backbone when they were killing Ukrainian civilians? or shelling near one of Europe's largest nuclear power plants? How about the illegal invasion and occupation of Ukraine in general?!
The Russian embassy should've been closed years ago. Jesus Christ Australia, grow a spine!