How exactly was this generated? Where are your sources? How are you calculating the center offset? Who would be someone today on the farthest left?
I got it from
www.politicalcompass.org
I figured that their style of graph would be so familiar, people would just recognize it. Apparently not.
They go through their methodology in detail in the FAQ on their site.
Also political leanings are relative anyways. So if you shift it based on the current political climate then the would get something more reasonable.
That would make it useless for comparing graphs to other graphs: the difference in mainstream political spectrums between countries or eras.
But this graph can be changed however you want depending on what you define the center as. And of course that's inherently subjective.
Read the FAQ. Their methodology is pretty reasonable. They based a "10" on any scale as the extreme seen in human ideologies, and then put the zero point midway between the two extremes.
Also its pretty insane that Trump and Bush are a step away from Hitler since presumably he's in the top right corner.
Hitler wouldn't have been absolutely far right economically.
And I think it's very fair to say that Trump and Bush are both at the extreme end of authoritarianism. The main difference between Hitler and most other authoritarians - i.e. that Hitler supported his authoritarian ideology with mass murder on an industrial scale instead of the traditional deportations, imprisonments, etc. - isn't really captured in the survey.