I didn’t know that back then, this was an American thing also….

Apparently, in 1939, New York was full of Nazis, they had chosen the date of George Washington’s birthday to gather 20.000 American Nazis inside Madison Square Garden.
They are seen with uniforms and flags, marching, and giving their typical antisemitic speech, which feels kinda strange outside of Nazi Germany:

https://youtu.be/O2-E5DHQMbY