The detention centre on

Manus Island was not a "concentration camp". 
There has been a rather nasty argument going on via Twitter between several people about the nature of the facility on Manus Island. In case anyone outside this country has been following that argument I have been asked to say something here.
The government sent unauthorised maritime arrivals to Manus Island instead of allowing them to come here. Whether that was right or wrong is a matter of hot debate.  The UNHCR condemned the centre but that is easy to do when you do not have to personally take responsibility. Others condemned it too. Again, it is easy to do that when you are not personally responsible for those there. 
It is also easy to say that the centre was a "concentration camp" but those who do that are being irresponsible. 
 The Manus Island facilities were never intended to be "nice". They were not intended to be some sort of "holiday camp". 
Despite that there can be no parallels drawn between the facilities there and the facilities in and purpose of places like Dachau and Buchenwald or a North Korean gulag.  
The detention there is now closed but, before it closed, some of the men there had to be forcibly removed. They claimed they were "safe" there and did not want to leave unless they were transferred here. 
Part of the problem is that people do not understand what the meaning of "refugee" is. People who, with good cause, flee their home countries  are considered to be refugees once they reach the first safe haven, normally a neighbouring country. They may not be welcome there but, unless they are in actual danger from the same matters which caused them to flee, they remain refugees in that country.
It is when people move on from there "in search of a better life" that they actually cease to be refugees and become what is best described as "economic migrants". We may still call them refugees and give asylum to those who claim to have a genuine fear of returning home but their status as a "refugee" is not longer clear. 
That has probably muddied the waters but is the best I can do in a limited space.
I would like to add something else, from my own extensive experience of those working with refugees. The first is that most people in the world's refugee camps simply want things to change in their own countries so that they can go home. The second is that, if they have documentation such as birth or marriage certificates or other ID, they do all that they can to keep it safe. The third is that, if they are offered a chance to go somewhere  which will be safer, they will usually take it. In other words they are often homesick, they don't destroy their documentation and they will accept a safe haven if it is offered to them.