Because Neitzsche was an enigma in many ways to many people who wanted to him to be somebody/something that wasn't what he was about. Nietzsche was not a democrat, nor a Marxist, an anarchist, a utilitarian, nor a man who followed any norms but his own. He gave his voice to speak on most things but never to be allowed to say he believed in thye universal and absolute. Unlike many ancient Greco-Roman philosophers and Enlightenment thinkers like Rousseiu, Locke, Thomas Hobbes, Adam Smith, Marx and Engels, Mills, and later Bertrand Russell, he said the 1# problem in the world is that they we think are by nature created equal in terms of character. It wasn't race, nationality, ethnicity, culture, that made us unequal, it was that human beings are unequal and have always been that way because of the essentials that define our own individual character. That's why he adores the Overman concept, the Will to Power, the Uberminsch is a person who is strong mentally, physically, self-controlled, and powerful. He doesn't make people come to see him. They come to him because of his personality, the traits that make him superior then most others.
One could mistake that as being a bit proto-fascist if you did the required twist to your own liking and left out the remaining essentials of what Nietzsche was explaining in the Will to Power, or Zarathustra. Hitler, Mussolini, Stalin even, saw this an affirmation because of what Nietzsche had said about a nation that gives up conflict is a society that gives up it's identity. But that again goes to show you that they saw this in terms of supporting racial nationalism, when in reality Nietzsche hated it, he broke with Richard Wagner because of Wagner's plays concerning and supporting German nationalism, and because of Wagner's anti-Semitic articles slamming famed Jewish German poet Heinrich Hemme, and because he was also reportedly smitten with Wagner's wife Victoria which certainly didn't help matters out very much.
IMO, His sister is the one that should be vilified for turning Friedrich Nietzsche into a more proto-Nazi ideologue. After falling out with her brother in the late 1880's, she and her second husband, a noted German nationalist and anti-Semite, went to Paraguay to set up a German colonial settlement(like quite a few others that were attempted in Central and South America in that time period IIRC) staying there until 1897 when second husband commits suicide and she goes back to her ailing brother in Switzerland who was in declining health(and would die in a few short years).
She and her brother never quite reconciled, but after his death and one of his contemporaries gave a eulogy who stated that his "name will be declared holy by future generations". That's where the problems began and in the end his sister along with a former publisher/friend of Nietzsche began to publish his novels, books, articles, commentaries, the whole nine yards, editing his work to show more of a clear fascist approach rather then the Individual Will to Power, it became WE instead of I will impose my power over you, the will to power is through US, not by Me, Force by will of power replaced by individual superior character over others.
It became an ends to a mean and in the end Nietzsche's work was almost permanently discredited. It wasn't until the later part of the 20th century after WWII that his name was at least partially restored and rehabilitated, and the complete context has been made clear to most people. It should also noted that Richard Nixon, JFK, President Reagan were avid readers of his novels and treatises, my God even Henry Kissinger counts himself as a man who fashioned his intellect and political upbringing partly on Nietzsche's ideals or opinions.
Nietzsche recognized that he was part of the culture that he hated. He was one of the hunchbacked academics that he criticized. For him the epitome of the Platonic/Christian culture is the person hunchbacked reading on a desk, denying themselves the pleasure of living. the fact that he was a great example of it wouldn't really bother Nietzsche in the least, imo.