It was through Propaganda and Silencing of people lead to people denying the fact that the holocaust was happening, and only rumors about concentration camps where among ally troops until they finally liberated them.
The holocaust was the mass genocide of jewish people by the nazi party so the so called "superior" german race could rule over Europe. Nazis beliwved jews were the rats that were investing Europe.
They were still segregated while they were in the U.S military. They even lived on a separate field even though they were fighting the same battles as the others.
