Here’s a link reporting on progress into the enquiry.
abc.net.au/news/2017-03-31/nt-royal-commission-a-look-at-whats-happened-so-far/8400796
As far as I can tell, the boys were both Aboriginal and white, so ethnicity doesn’t seem to have been a factor. I even suspect some of the guards were aboriginal or part aboriginal.
That said, the incidents were shocking and disgraceful. There may also have been a clique of guards known as “Jimmy’s boys” involved. The repeated use of the great Australian adjective doesn’t surprise me though.
On the other hand, when you’re dealing with criminals or dedicated juvenile offenders, the softly softly approach doesn’t work. Against that, jobs which give a clique power over others who are quite vulnerable seems to attract people who revel in that sort of sadistic environment - Gestapo, torturers, paedophile priests, authoritarian cops, abusive guards, and ISIS.
Here’s hoping the enquiry will solve at least some of the issues.
But since human nature is fallen, this sort of behaviour will be with us always, even if the locations vary, until the very end.