Ironically, though the charges of racism in his books are silly, this is inexcusable:
He's German. How is this any more sensible than interning Germans?
At the same time, this is what he thought of America First, a group supported by JFK, Gerald Ford, any several patriotic senators:
(This was published in July, 1941 and has no relation to a tiny party from 1944 which was probably a black-flag op against Republicans. The group he attacks here supported WWII after Pearl Harbor.)