To the amalgamation of politicals and criminals, with which the concentration camps began both in Germany and Russia, soon a third element is added, which would soon form the majority of all inmates. This largest group consisted of people who hadn't done anything that stood in any rational relation to their imprisonment, be it in their own mind or in that of their torturers. Without them the camps could have have existed, that is, they would not have survived the first years of the regime.
These in every sense innocent people do not just form the majority of all the camp population, they also are those, which finally were "exterminated" in German gas chambers. Only on them could the murder of the juridical person be performed so completely that they could be "processed", without names, deeds or misdeeds, by which they could have been recognized, in the mass factories of death, which just because of their sheer capacity could not take individual cases into account anymore. (A Jew for example, who had done a "crime" against the Nazi regime, didn't even get put in there in the first place, they were shot or beaten to death right away.) From the beginning the gas chambers were not intended as means to intimidate or punish; they were intended for Jews or Gypsies or Poles "in general", and they served to prove, that humans in general are superfluous.
While the separation of inmates into categories was merely a tactical-organisatory measure for the the purpose of administration of the camps, the arbitrariness of committal demonstrates the essential principle of the institution as such. The existance of a politacal opposition is just a pretext for the concentration camp system, and its purpose is not achieved when the population more or less voluntarily conforms as consequence of the most monstrous deterrence, that is, to give up its political rights. The arbitrariness has the purpose to deprive those under the totalitarian regime of all their rights as citizens, which finally become as outlawed [vogelfrei] in their own country as otherwise only the stateless and homeless. The deprivation of humans of their rights, the killing of the juridical person in them is just a precondition of their being totally controlled, for which even voluntary agreement is a hindrance. *[Related to that is the fact that all propaganda and ["Weltanschauungslehre"] was expressly forbidden in the camps. (also see Himmler, "Wesen und Aufgabe der SS und der Polizei"). And together with this in turn it has to be considered that that teaching and propaganda was also not allowed for the guarding elite formations; their Weltanschauung was not to be "teached", but "exercized" (see Robert Ley)]*. And this is not just the case for special categories of criminals, political enemies, Jews, on which it was tested [first], but for every citizen of a totalitarian country."Elemente und Ursprünge totaler Herrschaft", S. 658 ff.