Many Australians may wonder why it was necessary to set up detention centres in the far north of the country, or offshore, far from the Australian mainland, surrounded by guards and razor wire, in circumstances of great secrecy, with all staff and visiting medical personnel banned from telling outsiders about conditions in the camps, or reporting physical or sexual abuse of detainees.

Or why it was necessary to make it nearly impossible for lawyers or journalists to visit the centres. Or why the Immigration Department was allowed (or required?) to delay vital medical treatment to Hamid Khazaei, causing his death. Or send a raped and pregnant detainee for an abortion to Port Moresby (where it is illegal) rather than Australia; or delay the treatment or transfer to Australia of the man who committed suicide last week by setting himself on fire on Nauru?

Detained asylum seekers receive an intravenous drip because of dehydration at Manus Island detention centre.

When Nazi Germany set up concentration camps in the 1930s, the purpose was to separate various groups – communists, Jews, homosexuals – from the German community, to prevent them being "tainted" by such people. The camps were maintained in great secrecy; most Germans had little or no knowledge of the awful and dehumanising conditions in which detainees were kept.

Australia's detention centres in Nauru and Manus Island may have originally been intended to hold detainees for a short period – say, six months – while they were investigated and their claims to refugee status were assessed. But that has long since ceased to justify the existence of these centres.