Didn’t help when the President said it was a hoax by political opponents. There’s another segment that believes every word he speaks even though it changes constantly. Also doesn’t help that WHO & CDC said masks don’t help when they have been proven to reduce transmission. So misinformation came from the highest levels of government and experts. The media also didn’t take it seriously (not just Fox News). People formed incorrect opinions and as you said until they see it for themselves it’s not a big deal in their minds since everyone said that for weeks. Not sure if there is a technical term for this when one forms an opinion and won’t change it even when new evidence is introduced.