“Their last dying words are, ‘This can’t be happening. It’s not real’”: COVID-19 patients in denial: South Dakota ER nurse on Twitter

A South Dakota emergency room nurse reported on Twitter Saturday that some of her patients, short of breath on 100% oxygen, still insist that they don’t have COVID-19 because they deny that it exists. Her tweets were widely repeated and she gave an interview on CNN with fuller details, according to this article in the Washington Post on November 16.
“It’s like a horror movie that never ends,” related one of her Twitter posts. She told CNN, “I think the hardest thing to watch is that people are still looking for something else and a magic answer and they do not want to believe covid is real.”
This is one of the saddest things that I have read about this pandemic: the intensity of denial that some people display. They must have been indoctrinated to refuse to believe in something that is obviously real. Is it the television programs they have been watching? The main news network that has been pushing this denial is Fox, and others include One America News Network (OANN), Newsmax, and Sean Hannity.
Whoever has been feeding people these lies about something that is so obvious must have an ulterior motive. Is it because they make more money by promoting a conspiracy theory? Or are they invested in a lie that, once they start down that road, they can never backtrack? What is the reason which leads supposedly good people to tell such lies?
What is the reason behind this denial?