Fascism based in romantic philsophy: civic duty, natural law, and strength in unity while the left is based in enlightenment liberalism and rights of the individual which leads to Marxism rather civic duty to one's race, which is the only true nation. The right is Eugenics, and the left is dysgenic which is why one destroys civlizations and the other builds empires.
I'm sure you are someone who thinks Monarchism is left wing as well, showing you have an ulterior motive of labeling anything more authoritarian than Max Stirner leftist so there isn't an argument to be had here to begin with.
The diagonal line is the flattening your side of the fence does the political chart, you put fascism, monarchism on the left with Marxism, and anarchism on the right making it a diagonal line from communism to ancap child slavery like I said. Chart below is the argument you are making is flat out wrong.
RE: The "Alt-Right": Left or Right?