They weren't brainwashed by Fox News, they were turned into cult members by the right wing echo chamber. With Trump they learned that they could voice their opinion under freedom of speech and never look outside their bubble to see what the rest of the world thought. They simply want to remain stupid about everything that Fox News (and others) don't tell them. As we know from slavery, woman's suffragette and civil rights, this stuff takes generations to overcome. I don't expect this to be over any time soon.