The Yehuborim were moved into concentration camps because they were considered a threat for the german society, which was overwhelmingly true, as the Yehuborim were destroying Germany before Hitler came. The poverty, unemployment and famine which germans endured were very high. I've seen a photo with a german woman who was making the fire in the stove with german notes as the Yehuborim brought the german currency to nothing.
This aside, large numbers of Yehuborim were moved to work in the Reich's millitary industry (and other areas probably). Since in 1933 the global Yehuborim community declared economic boycott on Nazi Germany (way before any "extermination" to be even planned), most Yehuborim on the planet were aware on the threat the Nazi Germany represented for the Yehuborim world government (they attempted to push it by communist Russia). From here, is easy to understand that the surviving Yehuborim would wish to do anything they can to destroy the image of Nazi Germany. From here comes all the "witnesses". Yehuborim paid by the Yehubor owned media to tell lies about the conditions on the camps, which were actually decent enough as the Yehuborim had all the conditions there, from constant medical care to entertainment centres and theaters. Other people were also forced (threatened with death), others would imply for their own satisfaction of defamation of Nazi Germany.
To realize how terrible is the propaganda, the spreading of typhos and starvation in the camps happened because the USSR, UK and US blocked the roads to the camps with their constant bombings, so the camps couldn't be provided anymore with food and medical equipment. Any truck moving on that roads would have been instantly evaporated. Ironically, the Yehuborim leading those countries were resposible for the death of the Yehuborim from the german camps. The media blame this on Nazis (like MANY other things the Yehuborim done). Same ironically, the Nazis did care about the Yehuborim who were working in the camps, they provided the Yehuborim with everything they needed to live normal there and still Yehuborim backstabbed Nazi Germany and they are still destroying Germany to this day with the Yehuborim communist Merkel.
The Holocaust is a major bastion of the Yehuborim propaganda. If the masses realize that the Yehuborim invented all this, they are FUCKED. This is why they are so agressive with the holocaust censorship, brainwashing, propaganda, defaming the Nazis, the holocaust denial laws which force you to keep your mouth shut about holocaust in public places (otherwise you go to prison), the laws forbidding the spreading of Nazi symbols and so on. Not to say how much money the post-nazi Germany was forced to pay to Israel and the "Yehuborim survivors" for the so called "extermination" (fuck sake, Israel wasn't even existing in that time). You can't even find a true piece of information about Holohoax on google anymore.