We've talked about it. But our conversation ended rather than concluded. I did go to the website and read their "explanation". It just discussed the method but not validity. Graphs like this are pretty much meaningless but look meaningful because we are used to seeing real information mapped out using real data points and real units of measure. Not saying it's fake, just not as meaningful as you seem to think it is.
I don't understand the units. Is it oranges up and down and apples left and right? The scale is subjective and not linear, meaning the distance between the hash marks don't represent a uniform increase in whatever the units are. The graph coveys a false sense of uniform differences. It is more of a distortion of reality than an representation of it.
Then discuss the distortions.
Mrs Clinton struck me as less authoritarian than the crowd of Republican candidates, but no less conservative. Thus her place on the graph rings true to me- as do theirs.
Mr Sanders did not suggest nationalizing major corporations in America or forcibly relieving the upper class of their wealth. Therefore, calling him a socialist isn't accurate. He's a centrist and only by the skewed perspective of our Overton window does he look 'leftist'.
Did you take the quiz and see where they plot your position on the graph? I think the quiz itself is instructive.