Speaking as a former professional historian, no - they would not.
Hereditary rulers ruling by divine right are irrelevant to the discussion, plus they largely predate the whole right/left thing. Mussolini started as a socialist, as did Schicklegruber, though he is more debatable.
The main butchers (Lenin / Stalin / Mao) were all speaking for the proletariat of course. You do have some notable men of the Right (Pinochet, plus most of the military types, Chavez excepted), but most start out on the Left - virtually all the Africans, your Kims, Khmers, VC, etc. I don't know where you classify the religious ones (Iran).
I think the main tenet of the Left is "we know what's good for you"; well, how could you possibly cede power if you know what's best? Marx forbid, your opponents could undo all the "progress"...
One thing leads to another, and it turns out you have to kill the bourgeoisie. Well, and then those other socialists are not socialist enough, so better bury them too. Completely understandable.