Le Pen is too idiotic to realize that the purpose of the IG Farben factory at Auschwitz was to manufacture the lethal Zyklon B gas that was used strictly for the purpose of mass killing. Those "laborers" working at the "factory" were slaves used to help kill their fellow camp inmates. And the "laborers" would generally be sent to the gas chmbers themselves after they became too ill or disabled to work in the "factory."
I think you are absolutely wrong on this. There are many, many false stories about the Germans' labor and death camps, contra and pro national socialism. To understand really what went on, one should step back from a focus on gas chambers and consider that Auschwitz was a slave labor complex (synthetic fuels, rubber, some armaments, etc.). The complex was centered around Auschwitz-Birkenau and Auschwitz-Monowitz. The place was Utilitarian, in the most evil sense of the term. People were "sorted." Those who could not produce, were eliminated. Diet and disease-suppression were designed "optimally" to manage the input-output of the system. Labor was balanced by costs of nutrition and disease prevention.
The raw human material shoveled into the system came from non-citizen classes - Jews in Nazi occupied areas automatically fell into this group, but others did too, including "criminals." But the main objective of the system was not to kill Jews specifically, nor to kill anyone simply for the purpose of killing. That would have been a waste of resources. The point was to use human beings as industrial raw material. Culling the herd was indeed part of the program, but by focusing on the killing part this actually reduces the horror of what went on.
It is as if we are drawn to the gas chambers because it perversely comforts us. If what the Nazis did would have been irrational, non-human pure evil, we could say that it is not at all like us. We want Hitler to be Satan, his works outside of our comprehension, none of his works to be the logical extension of what we do in our every day lives.
On Auschwitz specifically and the "final solution" more generally, I highly recommend Richard Rubenstein's The Cunning of History.