You’re mixing up political positions with a set of attitudes.
The entire history of demagoguery in America shows that large groups of people will respond to a combination of “you’re really great if only you were given your due” and “you’re being held back by this group.” You can plug in a variety of specific villains - elites, liberals, communists, blacks, the Establishment, immigrants, Jews, urbanites, Catholics - to fit the moment. Once the villain has been identified, anything they say or do, and anything that they are claimed to have said or done, will be believed as a negative. It’s a proven technique that has worked over and over, and is obviously working today.
The point is not that all those Americans think a certain way. It’s that many of them have not thought and reasoned closely on a subject but have a vague set of dissatisfactions that will fit into a framework that is offered them on a platter. Once they adopt that framework, only time or extraordinary circumstances will change it, regardless of its relationship to reality. And yes, I am using terms this vague because they can be applied to other areas than politics and just as obviously are.