Why did the Nazis hate the Polish people?
Keep in mind, German-Slavic/Baltic hostilities had been hot and cold for centuries before the Nazis came to power in Germany. For ages, the Germans, then the rulers of the Holy Roman Empire, launched a series of “Crusades” against the Poles, Russians, and Baltic States (i.e. Old Prussians, Lithuanians, Estonians, Latvians, etc..) and conquered many of those nations and converted many of their peoples from Paganism to Christianity. Alexander Nevsky, one of the foremost heroes in Russian history, famously repelled the Teutonic tide at the Battle of the Ice near the city of Novgorod. Had he not prevailed, Russian history might have been very different. For instance, Prussia, once a Baltic state called Old Prussia (and now Slavic states, after the end of WWII) was captured by the Teutonic Knights, and the Livonian Order (both German Crusading armies) and was cleared of its Baltic population, likely via genocide, and repopulated with Germans centuries ago, becoming the infamous German State