For all that some Jews embrace Niemoller, he of the famous 'first they came for the communists' poem; he was a Nazi and enthusiastically supported Hitler until Hitler's policies, not those involving Jews of course, violated his Christian principles he also commanded troops in a right wing coup that predated Hitler and described Nazism as based on a 'solid moral christian foundation'
He voted for the Nazi party and made speeches on behalf of Nazism and Hitler. His difference with the Nazis came not over killing Jews but killing Jews who had converted to Christianity (a position he shared with the Catholic Church) but he remained an ardent nationalist even from Dachau, he wrote a letter volunteering to serve in the navy when WW2 began.
His allies attempted to pass off the letter as a forgery but when Niemoller was rescued, he admitted it was authentic and that he had "never quarreled with Hitler over political matters, but purely on religious grounds".
In other words Niemoller had not disagreed with Hitler only to the extent that Hitler disagreed with Christianity. Niemoller remained a despicable personage who milked sympathy for Germany while at the same time calling President Truman, the second greatest murderer in the world after Hitler.
After the war he developed ties to the Soviet Union, advocated against the Cold War, befriended the Viet Cong leadership and received many prizes and honors from the brutal Soviet regime while denouncing the West.
The famous poem he was credited with, never appeared in his writings or was credibly authored by him, though it has been attributed to him. Its actual source remains unknown.