I actually think that it’s hilarious – but for a reason that might be me giving it too much credit.
Hitler is chomping on a watermelon. Of course, Hitler’s regime was well-known for propagating the idea of aryan superiority – the Master Race – and a eugenics culture, claiming other races were inferior – including those of African descent. And, it’s also well known that the U.S. participated in the Berlin Olympics (not one of our finest moments) and that this Olympics was broadcast with one of the strongest television signals at the time all over the world as a show of Nazi strength.
The public embarrassment that resulted was when African Americans dominated – particularly Jesse Owens who broke 11 Olympic records in those games.
And the Nazi machine was known for it’s efficient visual propaganda campaign, portraying those of other races – including anti-black propaganda meant to scare people about “race mixing.”
The mid-20th century classicly racist image of the black man was that of the slow-witted man on a porch – eating a watermelon. As @jaytkay just mentioned above.
So…maybe I’m not wrong that this was intentionally as smart as I thought it was. It’s a wonderful sort of meta-commentary.