Doesn't mean that Trump can be compared to Reagan simply because both were registered Democrats.
That's the angle here. Not that every single one is a mutually exclusive case.
You made a broad brush statement. I offered an example that proved you wrong. The New Deal crowd was a coalition of Socialists, Communists, Populists, and Racists. If anything, there are fewer Communists and Populists in the Democrat party today, but it is still full of Socialists and Racists.