I can understand the confusion - at one time or another almost every modern minority group has claimed to have been targeted by the Nazis - in short, the Nazi’s were strongly focused on strengthening the then down-trodden German people - they targeted any groups that either weakened the strength of the state from within or opposed it from outside - Jews and Roma (gypsies) were seen as groups that never integrated into the German society and instead lived in Germany exploiting the German government for money without contributing or adapting to its culture -It is heavily suggested in Mein Kampf that Hitler never forgave the Jews for Their part in Germany’s “forced surrender” that ended the First World War - Polish nationals and other citizens of surrounding countries were killed as ‘Prisoners of War’ to prevent them fighting against Germany - Some Religious groups, notably the Jehovas Witnessess, were targeted because they encouraged German converts to not be fully faithful to the state - in some cases Homosexuals who refused to contribute to the reproduction of much needed German people were also killed - resources were limited and the German focus was entirely on survival and winning the war - as such, any “burdens” to the government were also removed; this included mentally unstable people and people with disabilities