I do not understand why people are so intent on denying reality. There are no reason to doubt the Holocaust. The historic evidence is overwhelming and the policy of exterminating ones enemies follows logically from Nazi ideology.
The Nazi's lost the war because they were evil and evil tends to self destruct. If Hitler had given Ukraine independence instead of brutally subjugating it and worked to build a White Russian liberation army out of his 4 million soviet prisoners of war from Operation Barbarossa Nazi Germany while limiting his territorial ambitions on the Russian heartland he would have had a shot at winning the war and destroying the USSR. However, such actions are incompatible with the Nazi ideology which viewed the Jews as a poisonous race and the Slavic peoples as a race of slaves in need of a master. The USSR was pretty evil too so it takes something really special to make them into good guys.
Nazi Germany did its very best to exterminate all its enemies military and civilian. Between June 1941 and January 1942, when the Germans killed an estimated 2.8 million Soviet POWs primarily through starvation. The entire German assault on Russia in Operation Barbarossa included only 4.5 million men which was around 80% of the German army at the time. For the average Russian Stalin was a horror but the Nazi's offered them only extermination and death in his place.
Russia had no choice it was either fight for continued existence or surrender and face death and slavery. A people with nothing to lose will fight to the death. This is what allowed a Russian army inferior in every way to ground down and crush the Germans with sheer numbers and blood. The best documentary on WW2 that I have seen is a soviet one tells the story of world war two from a Russian perspective (link below).
https://www.youtube.com/watch?v=JhXKlYnSWjAThe Nazi's were very good at killing their enemies. They did the best they could to kill every Jewish person in the world. They killed about 40%. They also did their best to wipe out the Russians 12.5% of Russians were killed in WW2 and even 16.5% of the Ukrainians who were largely opposed to the soviet union and initially greeted the Germans as liberators. The tremendous casualties in Ukraine (which could have been a Nazi ally) highlight the insanity of the the regime and the inevitability of their defeat.
Given the Nazi's view that this was an existential struggle and their views that the Jews were poison and the Slavs rebellious subhuman slaves mass extermination and oppression is the logical policy. It is the result of a grossly twisted worldview.
Here is a link to a speech given by Hitler describing his reasons for invading Russia.
https://www.youtube.com/watch?v=0hYDx2LtLv4He believed the Soviet Union was a threat to Nazi Germany and he was probably right about that.
However, the Nazi's also believed that strength alone gives one the right to to exterminate and dominate others. That is was acceptable to conquer and exterminate another people to make living space for ones own people. It is this lack of morality that leads them to the very policies that result in their inevitable defeat.
