I agree that the characteristics of Nazi Germany began much before Hitler. Many do go back to Bismarck, father of the modern social welfare state.
But the comparison of the modern US to Nazi Germany is no less valid because of that. The history of the governmental changes just shows how easy it is to slip from “benign” social welfare statism to totalitarianism.
Put another way, how easy it is to turn the heat on to “boil” once you have the frogs used to warm water.
Weimar attitudes and Weimar politics did the job.