There's three different categories here: 1) People that didn't know there were internment/concentration camps at all. 2) People that knew there were camps, bu

There's three different categories here: 1) People that didn't know there were internment/concentration camps at all. 2) People that knew there were camps, but didn't know about the murder/torture/etc. They earnestly believed these camps were for detaining prisoners, like the American camps. 3) People that knew everything. Given that Americans knew about their own camps--and did nothing--I'm inclined to believe that #2 was by far the largest group, while #3 was relatively small. Also, keep in mind that censored internet is one thing, no internet and fascist death squads keeping everyone in line is an entirely different level of suppression of free speech.