Just a story. Skip it if you wish. My husband’s family is Jewish, wonderful people from the Mississippi Delta area. Just prior to WWII his grandfather made multiple transatlantic trips to beg and plead with their family to come with him back to the United States. All but one thought that they would be fine. The one who came was a young doctor on the last ocean liner out before the beginning of hostilities. A German submarine surfaced and boarded the liner, looking for Jewish refugees. She positioned herself on deck against the railing and was determined to go overboard rather than be captured. She completed her medical credentials and became quite prominent in the area as a doctor and administrator. Cousin Elsbeth. There is no record of the family that stayed behind.
For one thing the Germans, as was and is their nature, kept very precise records and what most people don't realize is that the death camps were just the final act. As many or perhaps more were killed by the "task forces" (Einsatzgruppen) or mobile killing squads sent into Poland and the Soviet Union as the regular army forces took territory. It was all thoroughly documented and anyone who would deny it is either an imbecile or is operating from the most evil of motives.
Who knows how many people who would have become brilliant scholars, scientists, and doctors were killed because of the irrational obsession of one loser who happened to have a talent for demagoguery? Certainly a large number.