For hundreds of years the people in Europe considered tomatoes to be pionsioius. Eventually the people came to realize the error and began a love affair with the delicious fruit they once feared.
When people have a belief they experience cognitive dissonance when they are introduced to a new idea that contradicts what they believe. The person is faced with a dilemma of choosing to change what they believe or choose to reject the new idea.
Like the Europeans who were taught to fear tomatoes, the people in the United States have also been taught things that are simply not true. Practically everyone in the United States believes that Abraham Lincoln was a national hero who freed the slaves.
When people are introduced to new information that reveals that Abraham Lincoln did not fight a war to free the slaves and that he was in fact a white supremacist they cringe and reject the truth without even bothering to study the evidence.