About Prussia, the Teuton Order massacred large numbers of the native Baltic tribes when they invaded. When the Kingdom of Prussia formed, it was really just a prestigious title for the Margrave/Elector of Brandenburg, around which the Kingdom was centered. This is incidentally why Berlin was the capital. Prussia was just a name, not the actual ethnic group.
EDIT:
Also, though this is just my opinion, I think much of the original anti-Polish sentiment was because of Prussia wanting to connect its land in the Partitions. Then, the Polish were against this for obvious reasons, and the monarch was against this. Not really nationalist sentiment. That came after Napoleon for the most part, and originally had even supported an independent Poland. After 1848, the conservative part took over, leading to much of the discrimination. I agree with you about the rest, except the Germanization of the Midwest, which I am confused about.
Prussia was a polish land, fief.. Given more power as time went on.
The original Prussian were germanized - noting that original Prussian were more more ( Lithuanian, polish)
Power grants or waeewbra keeping and moving up..
Prussia in the long run did more for German unification than anyone since charlamagne. People hate Prussia for being the upstart.. I don't..
One can hate them for the flaws.. But hating Prussia because it was strong and ahead of the game is just crap history.
Also judging Prussia by modern standards is also hogwash. Peuah interwar was actually fairly democraric. Granted come the nazis, they pressed the buttons to push the imperialistic nationalism. Prussia was Germany just as much as Germany was Prussia.
Biggest Prussian problem was not outgrowing the old ways after ww 1. That said Noone else did either.
Second issue was less objection and their was to the nazis, problem being loyal or in a concentration camp yourself.
Damned if you do and damned if don't.
Hitler wasn't Prussian.. Not in name, rank, life or even by drinking in Bavaria (which also wasn't Prussian)
In a conversation about German nationalism and including the Jews in it, I see no reason why the Prussian if even remotely pushed wouldn't.
Who is pushing.. Many people who went on to do very bad things were encouraged to do so or high jacked or were promoted by a system that promoted the hate.
Prussia and the German empire were not perfect... They did bad things like every nation... But nazis no.