I'm a big believer in the power of examining history to understand current society. For example, Gordon Craig makes an interesting case that the particular results of the Revolution of 1848 in Prussia were a substantial cause of the rise of the Nazis.

But it is important to recognize the limits of historical analysis across long periods of time. First, multiple causes blend together, making it very difficult to disentangle causation. More importantly for this conversation, moral changes are not discrete events.

Thus, trying to figure out the moral changes from the 1670s and 1680s that causes the French Revolution to have a Reign of Terror while the America Revolution did not seems to be asking too much of historical analysis. Looking before 1650 seems even worse.