The falling out between Stalin and Hitler was merely an issue of methods for establishing a totalitarian state. They were both statists to the nth degree.
Don’t put them at opposite ends of a spectrum. It was a falling out among thieves. Do the gang wars of Mexico warrant classifying rival gangs with different ideological categories on opposite ends of some spectrum? “Academics” who do this with Nazi’s and Communists are shallow thinkers.
Classical liberalism held up the rights of the individual. Modern liberalism upholds the supremacy of the state over the rights of the individual. The redefinition of the term “liberal” occurred in the first half of the 20th century.
Democrats, Communists, Socialists, Stalinists, Nazis, and others of their ilk have no regard for individual liberty.
The Democrats have totally confused equality of opportunity with equality of results. They intend to reach the latter by employing the power of the state. The “state” determines what is “fair” and who is giving their “fair” share. Thus, they should be lumped in with other statists.
Scholars and the popular press put extremist ideologies on the opposite sides of the political spectrum because they had an emotional heat that more moderate and accommodating politicians didn't have.
It's good to get beyond the simplistic Nazis = right-wing, Communists = left-wing scheme, but if it's just replaced by a me = right-wing, everybody I happen to disagree with = left-wing scheme, there are still a lot of problems that haven't been ironed out.