Are all humans equal, Or are they only "supposed to be" equal?

Chapter 10: Chemical Examination
Here in chapter 10 Primo Levi takes a chemical exam with which he could improve his status in the camp if he takes it well. A person called Doktor Pannwitz supervises the test taking, as he asked questions to Levi and other candidates. During the test, Levi expresses his views on Doktor Pannwitz’s stare: “…that look was not one between two men; and if I had known how completely to explain the nature of that look, which came as if across the glass window of an aquarium between two being who live in different worlds, I would also have explained the essence of the great insanity of the third Germany.”
This quote shows how there can be a great distinction in status of two humans, caused by a persecution of a group of humans by another. Although both Homo sapiens, Doktor Pannwitz was definitely more well-off than Levi. While Germans are enjoying a normal life with adequate food, clothes, and shelter, the prisoners in the concentration camps, persecuted by the Germans, do not even have a sufficient amount of these three necessities of life; they are not even treated as humans. Yet both are “humans,” who are essentially equal, at least under God.
I felt that it was ironical how such a distinction could exist between two peoples; this not only happened in the Holocaust, but all throughout history and even now. Wealthy people enjoy luxurious and lavish lives, while the needy struggle to survive in harsh conditions. I wonder how strange Levi would have felt as his status was degraded, and he realized he was in the lowest form of a human. Actually, by the time he took the chemistry examination, he would have been used to this.