LI had more than a few German-towns. New Hyde Park still has a couple of dozen octogenarian Germans holding on to the houses they bought in the 40s. And, I am currently working on a script entitled "Polishtown" set in Riverhead and the Hamptons.
You have to keep this kind of stuff in perspective. In 1937 here's what German-Americans knew:
Germany had been totally screwed by the French after WWI (which they and Russia had actually instigated over Germany's alliance with the Hapsburg Empire, which was cracking down on the Serb terrorists who had assassinated their Arch-Duke) and their economy was in the toilet, as was their corrupt Weimar culture. Hitler was, at that point, merely reuniting a dismantled nation.
Hitler was an anti-semite. He was also an anti-communist. Both before and after the Molotov-Ribbentrop pact, you could make the case that Hitler was much less a threat to America than Soviet Communism. There had been no holocaust in 1937.
Sure, these people (and the ralliers at Madison Square Garden who were giving the Nazi salute before a giant banner portrait of George Washington) were misguided given who Hitler turned out to be. But it doesn't say anything horrible about their character. Certainly nothing as horrible as could be said of people who should have known better regarding communism. I give you Alger Hiss, Edward R. Murrow, Dean Acheson, Franklin Roosevelt, Henry Wallace, Walter Duranty, and three whole generations of pro-soviet liberals and traitors who have NEVER been called to adequate account for their treason.