It's hard to adequately describe just how much Nietzsche despised anti-Semites. He even disowned his own sister for her ties to anti-Semitism when she married a fascist. In a letter near the end of his life he wrote that all anti-Semites should be shot.

In Beyond Good and Evil he wrote that he, as an artist "among the spectators and philosophers", is grateful to Jewish people for their contribution to European culture, and that it would be "fair and useful" to "to banish the anti-Semitic bawlers out of the country."

Anti-Semites claiming him as their own enraged him. The anti-Semitic writer Theodor Fritsch liked Nietzsche and sent him his writings, and Nietzsche responded saying “I ask in the future not to provide me with these [anti-Semitic] mailings: I fear, in the end, for my patience.”

“these constant, absurd falsifications and rationalizations of vague concepts “Germanic,” “Semitic,” “Aryan,” “Christian,” “German” - all of that could in the long run cause me to lose my temper” - “how do you think I feel when the name Zarathustra is mouthed by anti-Semites?”

Nietzsche often praised Jewish people, actively hoping it would upset anti-Semites. He wrote that the Jews "are a people gifted with the very strongest vitality”, and in Beyond Good and Evil called them "the strongest, toughest, and purest race at present living in Europe."

He distanced himself from racist views of his time, saying "Where races are mixed, there is the source of great cultures." And, referring to racist Germans, made it a maxim "to have intercourse with nobody who has any share in the mendacious race swindle."

And he didn't like the Germans of his time at all: “Germans have no idea how vulgar they are, but that is the height of vulgarity—they are not even ashamed of being just Germans”. “If I try to imagine a type repellent to all my instincts, it’s always a German who comes to mind”

"...we are not nearly "German" enough, in the sense in which the word "German" is constantly being used nowadays, to advocate nationalism and race hatred ... For that we are too open-minded, too malicious, too spoiled, also too well-informed, too "traveled"."

"We who are homeless are too manifold and mixed racially in our descent, being "modern men," and consequently do not feel tempted to participate in the mendacious racial self-admiration and racial indecency that parades in Germany today"

He also hated nationalism, calling it “this national neurosis from which Europe is sick". “Being nationalistic in the sense in which it is now demanded by public opinion would...be...not mere insipidity but dishonesty, a deliberate deadening of our better will and conscience.”

It's incredible then that one of the biggest movements that tried to claim Nietzsche as his own was German Nazism. This was made possible partly by Nietzsche's sister fabricating The Will to Power, presenting it as Nietzsche's magnum opus, when it was not in fact compiled by him.

The main Nazi popularizer of Nietzsche, Alfred Baeumler, not only considered the forgery that is The Will to Power Nietzsche's most important book, he undermined Nietzsche's ACTUAL published works saying they make it "difficult ... to see the unity of his life's work."

Baeumler threw away key Nietzschean concepts as he wished, most notably the eternal return and the Dionysian. What he wanted is to systematize Nietzsche in a way that supports Nazi ideology while removing all ambiguity from his thought - to turn Nietzsche into a lifeless carcass.