Adolf Hitler was a national-sociopath. However, he was also a human being. Consequently, his decisions and actions were not only about Germany, but about him as well. In other words, they were intensely personal.
Like any political genius (and Adolf Hitler obviously was one), he had an enormous and extremely vulnerable ego. Which was severely, devastatingly hurt in 1907-08. In one short year, he was rejected by the Academy of Fine Arts in Vienna (twice), lost his mother (the only person he genuinely loved and on whose love he was heavily emotionally dependent) and from a comfortable middle-class life sunk to the very bottom of the Austrian society.
These three catastrophic events created an extremely powerful drive that heavily influenced all his decisions and actions – to his very last day. They created formidable feelings of failure, shame and humiliation. Feelings that inevitably transformed into virulent hatred.
This hatred can be implosive, explosive, or both. Implosive hatred is directed towards oneself and very quickly manifests itself in self-destructive behavior – alcohol, drugs and suicide attempts.
Explosive hatred is directed at external objects – individuals, social groups, nations, races, social structures/systems (e.g., Austrian government) or all of the above.
His anger was explosive. At first, it was directed towards the abstract “world”. His friend Kubizek later recalled:
“Choking with his catalogue of hates, he would pour his fury over everything, against mankind in general who did not understand him, who did not appreciate him and by whom he was persecuted and cheated”
Later his hatred got more specific. It was directed towards the Jews, Marxists, Slavs, the Austrian government, parliament (any parliament), democracy, etc. Which made his “sociopath” part thoroughly irrational.
Which, in turn, resulted in fundamentally wrong (and ultimately disastrous) decisions and murderous actions, including the Holocaust and other war crimes and crimes against humanity.
This hatred produced an immensely powerful desire for revenge. Revenge both benevolent (a burning, overwhelming desire to succeed against all odds) and highly malignant – destroy and even murder the objects of his hatred.
A rational national-sociopath seeks only to exploit other nations for the benefit of his own and wants to get the most in terms of aggregate value (financial, functional and emotional) from. Which usually requires making these nations the servants of his nation and treating them well enough to get the most out of them. Hurting (let alone destroying them only if absolutely necessary).
An irrational national-sociopath (and Adolf Hitler undoubtedly was one) seeks to make other nations the slaves of his nation. Not a good idea because slaves are not productive at all.
To humiliate them, hurt them and even destroy them. Which again is a bad idea, because it only makes them even less productive. And the dead do not produce anything at all. So murder is a very, very, very bad idea from the purely functional, rational perspective.
Besides, Adolf Hitler undoubtedly never heard or read the old Chinese saying “Before you embark on a journey of revenge, dig two graves” (actually, it was Confucius who said that). Because it was exactly his overwhelming, totally uncontrollable desire for revenge at any cost that ultimately killed Adolf Hitler.