Regarding knowledge of the camps, the "fear of becoming the next victim" is the context. It is always the context when authoritarian movements rise up.
The Nazis didn't go after the Jews first, they went after Germans of any race/religion that wouldn't conform into their hierarchy. From this
Holocaust Museum page,
From its rise to power in 1933, the Nazi regime built a series of incarceration sites to imprison and eliminate real and perceived "enemies of the state." Most prisoners in the early concentration camps were political prisoners—German Communists, Socialists, Social Democrats—as well as Roma (Gypsies), Jehovah's Witnesses, gay men and men accused of homosexuality, and persons accused of "asocial" or socially deviant behavior.".
After Germany's annexation [Anschluss] of Austria in March 1938, Austrian political prisoners came into the Nazi concentration camp system. Following the violent Kristallnacht ("Night of Broken Glass") pogroms in November 1938, Nazi officials conducted mass arrests of adult male Jews throughout the country, the first time Jews were arrested en masse precisely because they were Jews. Over 30,000 German Jews were incarcerated in the Dachau, Buchenwald, and Sachsenhausen concentration camps in Germany, initially until each could provide proof of their ability to emigrate.
So, the German people had five years of seeing persecutions of
other Germans. Five years of feeling the "fear of becoming the next victim". Plenty of those Germans were already willing to be a part of the Nazi movement, but many were coerced into silence and obedience during that time. This is where the real "brain-washing" comes in; that triggering of the body's fear chemicals to condition the individuals to respond in a particular way; all because the mind is attempting to perceive a path to survival.
If you had 5 years to think about it, would you choose to be a Nazi parrot or to get listed as an enemy of the state?
The camps... There were only 6 death-camps, but there were 30,000 work camps. From this holocaust-disambiguation site
Number & Types of Camps"Between 1933 and 1945, Nazi Germany and its allies established more than 40,000 camps (slave labor (30,000); concentration (980); POW camps (1,000); “care” centers; internment and killing centers (6)) and other incarceration sites. The perpetrators used these sites for a range of purposes, including forced labor, detention of people thought to be enemies of the state, and mass murder. The total number of sites is based upon ongoing research in the perpetrators’ own records."
Authoritarianism in a nation and in a home are very similar. When you see a family that is in fear of the potential anger from its dominant leader, you see how it is easier for them to accept the yoke than it is to fight the yoke. Then, that same family will stay silent when atrocities happen against family members.
In the same 1930's timeframe, Russia had their camps...
This vid explains how the gulag system's records and internal communications were used to understand how Stalin's gulags had about 1/6th of the overall population in them.
And the current Russia... they are trying to consume Ukraine, just like Germany consumed Austria/Hungary/Czech.
Filtration camps, moving Ukrainians into the distant regions of Russia where there is no escape.
And then, among the things the US's GOP Project 2025 people have been spouting, more camps.