The real disservice of this sort of this sort of stuff is how flagrantly obvious they make the bad guy. Yeah, everyone can identify the idiot spouting off about skin color and engaging in an un-obfuscated textbook exercise in divide and conquer as probably not worth listening to. Patting yourself on the back becase you can identify it when it's flagrantly obvious is counterproductive. The guy in the internet comment…
The problem is that people are still falling for exactly the same sort of comic-book evil even though it's every bit as obvious. e.g. Haitian's eating dogs, illegal immigrants scamming medical services, stealing high-paying jobs, etc.. A high percentage of people completely lack what Carl Sagan would call a "Baloney detection kit", and the current purveyors of baloney like it that way. That's why they're anti-science…
Anti-Nazi propaganda from WWII has been a staple of American and broader Anglosphere culture for the entirety of my life; and so has the counter-phenomenon of people deliberately using Nazi symbols to be shocking or provocative.
Anyway, at the time this film was produced by the US government, legal immigration from foreign countries to the US had been heavily curtailed for a generation by the https://en.wikipedia.org/wiki/Immigration_Act_of_1924, and immigration would not be liberalized until another generation later in the 1960s.