Hitler rages against and wishes to destroy "Jewish parasites." The parasite, in actuality, is Germany--the "immortal object" with which Hitler identifies. The parasite is Hitler's own fantasy of immortality, the German nation, to which he has sacrificed his existence.

But Hitler cannot acknowledge that Germany is the parasitical object which torments him, because this would mean abandoning Germany, the object that torments him--his own fantasy of never-ending existence.

So, Hitler projects the idea of the parasite onto the "eternal Jew." It is not his devotion to Germany that is draining his life, depriving him of his human existence. Rather, it is the Jewish parasite that is draining--depriving him--of his human existence.

But the Jew is a projection of the parasite within Hitler, the German nation which Hitler refuses to (cannot) abandon. The parasite is Hitler's own fantasy of eternal existence, which torments him but from which he is unable to separate. 

Given his ambivalence, Hitler would have to wage endless war against the parasite, to kill Jews forever--to kill each and every Jew in the world--in order to liberate himself from the object that torments him. 

Hitler's struggle (Mein Kampf) could end only when he killed the source of the parasite, himself, the Jew within his own mind and body, Germany.