It is from a slightly older novel, Pat Miller’s Willfully Ignorant from 2014.
The propagation of a fake quote like this raises some questions.
One could ask about the thought-processes of the person who decided to take a sentence from a novel and to misrepresent it as a quote from Adolf Hitler. Obviously such a person has no scruples.
More important, however, is what it says about the people who readily embrace such a misrepresentation.
In the first place, it shows that, despite the obsession with Adolf Hitler in popular culture, much of the general public knows practically nothing about him. They never perused Mein Kampf to get a general idea of what Hitler said — which is rather the opposite of what is attributed to him here. The whole spirit of Mein Kampf is blunt and honest.
Furthermore, it suggests that they are still under the influence of old war-propaganda alleging that Hitler presented in Mein Kampf theories about how to deceive the public. Anyone who investigates what Hitler wrote will find that he warned against the Big Lie as a tactic of the Jews. But the vast majority of people will never check, and the few who have checked either could not or would not obliterate the false belief.
Dinesh D’Souza, in his public presentations about his idiotic book The Big Lie, speaks as if Hitler had advocated the Big Lie. D’Souza indicates in his book that he knows better, but for whatever reason he chooses in his public presentations to conform to the old, false propaganda. The fact that he can do this in presentations at universities without suffering embarrassment is remarkable. Perhaps the people who recognize the deception just don’t want to be seen defending Hitler. (Many of Dinesh D’Souza’s followers however are simply stupid.)
The belief that Hitler would have written such statements in a book for publication also shows an utter lack of critical thinking.
The statement shown here resembles something from The Protocols of the Learned Elders of Zion, which was alleged to be a secret document that ended up being published only because it was leaked.* There is no similar background story to explain how similar admissions from Hitler could become public. We are supposed to believe that Hitler deliberately wrote down his evil intentions and had them published. People are just not thinking.
* Incidentally, Protocols is clearly not an authentic document either, although, unlike this statement attributed to Hitler, it at least has some resemblance to the truth.