So he is German. OK.
But Marie Curie was born in Imperial Russia (Vistulan Country to be exact) and never lived in Poland. So she must be Russian. And Chopin was born in the Duchy of Warsaw, which was part of the French Empire, so he must be French. Or is he Russian because he lived most of his life in Russia?
Doesn't seem like Germans were willing to recognize the "Pollock" as one of their own, does it?
Wow! A German speaking about somebody he doesn't like and wants to call that person a Pole instead of a German. Who would have thought that was possible! Unfortunately, your translation appears to be at odds with that of other people. Hermann Kesten (Copernicus and His World, NY: 1945, p.309) and Will Durant (The Reformation, vol. 6, The Story of Civilization, 1967, NY: Simon & Schuster, 1957, p. 859) both quote Melanchthon as saying "Prussian".
But instead of just listening to other people's opinions, let's look at the facts:
Name at birth: Niclas Kopernik, not Mikołaj as Poles say, Copernicus never signed his name with an M, always with an N.
Father: Niclas Kopernik, the family name can be traced to the town of Koppernigk near Neisse in Silesia. Birth place not known. Not a Polish citizen at the time of Copernicus' birth.
Mother: German. Like her parents.
Birthplace: Thorun, Prussia.
Name when at Krakow university: Nicolaus Nicolai de Thorunia, not Mikołaj
At Bologna university he joined the German school especially established by the Vatican to educate German clergy, the "Natio Germanorum".
There is no evidence that he spoke Polish, lots of evidence that he spoke German.
In his memorandum on coin reform in Prussia he wrote about Prussia as "Us".
On several occasions he called himself "Prussian".
I'm not seeing a lot of reasons here to call him a Pole.
I'll sum up your argument: Copernicus is Polish because he was born in a place which is historically Prussian but was at the time under Polish jurisdiction at the time of his birth and because his father might have been Polish (because he might have been born in Poland but we don't know for sure where he was born). By that same logical Marie Curie is Russian: she was born in a place which at the time (1867) was under Russian jurisdiction and both her father and mother were also born in what at the time (1832 and 1834) under Russian jurisdiction so they were Russian too.