German-Jewish historian Samuel Igra, in his 1945 book Germany's National Vice, suggests that a probable reason for Hitler's anti-Semitism is traditional Judaism's opposition to homosexuality
At the age of 16, Hitler moved to Vienna. A young man called August Kubizek joined him and they lived together for four months. Intensely jealous, Hitler wrote to Kubizek, "I cannot endure it when you consort and converse with other young people."
Hitler spent five months at a men's hostel known as "a hub of homosexual activity."
Hitler's rise largely was due to his close friendship with two homosexuals: Ernst Roehm and Dietrich Eckart.
Lothar Machtan, a professor of history at Germany's University of Bremen,writes in his book "Hitler's Secret - The Double Life of a Dictator" that Hitler had relationships with a number of men in his youth.
"We can say that Hitler had several homoerotic friendships up through the1920s," Machtan told Die Welt newspaper." Many of them would be described by people today as homosexual."
Hans Mend, a stableboy who served with Hitler in World War I, said: “We noticed that he never looked at a woman.... In 1915 we were billeted in the Le Febre brewery at Fournes. We slept in the hay. Hitler was bedded down at night with ‘Schmidl’, his male whore. We heard a rustling in the hay. Then someone switched on his flashlight and growled: ‘Take a look at those two nancy boys’.”
Eugen Dollman, Hitler’s interpreter, said that in 1923 he had heard a general in Munich reading from a police file in which young boys claimed that Hitler had paid them to spend the night with him.
The Night of the Long Knives in 1934.
Rohm, who had been with Hitler at the start of the Nazi movement, was a homosexual. Machtan says Rohm was one of very few people who knew about Hitler’s homosexuality. “It must have been Hitler’s nightmare that he would one day launch a smear campaign.”
Rohm was one of about 150 murdered in the Night of the Long Knives. Machtan says the “principal motive” for the slaughter was Hitler’s fear of blackmail.
Machtan refers to Hitler’s “poses,” “gestures and body language,” “his accessories (moustache, whip, etc.),” his “effeminate cast of feature, his taste for muscular, monumental art,” and “the marked pleasure he derived from contemplating the male physique".
Machtan claims Hitler was never very interested in women. His relationship with Eva Braun was almost certainly platonic.