Thank you for getting these two reasons above water, Benjamin.
Yes, it is important to understand how the discipline of history operates. But the answer to this question lies with the discipline and not with the examples we may find themselves. One important part of understanding this discipline is that the veracity of information peters out. If we cross that line, then we walk into the area of inference in which few facts are available. The discipline with few facts can cause a groupthink to occur with people desiring clear answers, providing clear answers, people being satisfied, but where the clear answers are in reality of a misty quality.
Yes, a culture can make an entire population turn a blind eye to facts. This is probably quite common and happens at the smaller and at the larger scale. Russia today is a good example which I do not need to explain. The USA is a similarly good example because folks confirm what they like and ignore what they do not like. We pass by the homeless on the streets, may give a dollar or not; we ignore the fact that the USA has the largest percentage of its population in prison in the world; we don't question the political system that is red and blue, and does not show us anything in yellow, green or orange. The list is endless, just here at home. People exists in a man-made reality to the point nature is actively destroyed.
I hope you see that I like your answers, but that they lack satisfying depths. They are not bringing real answers.
What is your deeper desire with this path you are walking?