I remember the pastry argument from that time. Here is one interpretation regarding JFK’s speech.
“What is the meaning of “ich bin ein Berliner”?
To state Ich bin Berliner would have suggested being born in Berlin, whereas adding the word ein implied being a Berliner in spirit. His audience understood that he meant to show his solidarity. Emboldened by the moment and buoyed by the adoring crowd, he delivered one of the most inspiring speeches of his presidency.”
Elsewhere it was stated about this doughnut that while “ein berliner” is its name in Berlin, in other parts of Germany it has a different name.
Yes, you are right. 😀
Spherical doughnuts with a filling of jam (or sometimes custard or lemon curd) are also popular in Poland, where they‘re called pączki, and iirc they are very popular in the USA, too, especially among Americans with Polish roots.
In the dialect of the Palatinate, where President Trumps forefathers came from, they are called „Kreppel“ (singular and plural), though this term is now considered obsolete in Standard German 😀
A Polish friend once laughed when I told him about this, and he said that Old Polish used the exact same word, because the custom of preparing deep-fried foods on Fat Thursday, when all fat in the house had to be used up for Lenten fasting, had been introduced to 10th century Poland by German missionaries.