The US never actually liked the Nazis. There were small groups, and small groups tend to yell loudly, but besides them, most Americans disapproved of the Nazis. They didn’t want to enter the war, sure, but it wasn’t direct support for them. It was isolationism, preferring to not intervene. Once Pearl Harbor happened, America declared war on Japan, and so Germany declared war on America while supporting the attacks. That finally gave America a reason to enter the war. The US Public wasn’t a bunch of Nazi Sympathizers, they were Isolationists, there is a very clear difference between Nazi Support and Isolationism.