Look at the French Revolution for a study of how movements arise, move to their extremes, give rise to their reactions, which then move to THEIR extremes, and finally settle on some new course that, in many cases, is no better than the original.
Napoleon was hardly less of a tyrant than Louis XVI. Hitler was no better than the Kaiser. Stalin didn't improve much over the Tsar. And Castro is certainly no better than Batista.
The list goes on and on ...
Hegel?
Are you crazy? Hitler was far worse than the Kaiser. Stalin was much worse than any of the Czars. Castro was much worse than Batista. Cube used to be one of the wealthiest in the Americas. Quality of living dropped way down.