Wait, all of your examples are examples of mass violence being unleashed as a result of a conversion from an already existing non-democratic, non-utopian govern

Wait, all of your examples are examples of mass violence being unleashed as a result of a conversion from an already existing non-democratic, non-utopian government to a democratic form of government (which incidentally often has has explicitly utopian goals). Your proper decision point isn't "Do I choose liberal democracy or fascism"; it's "given I live in Wilhelmine Germany, do I start a revolution to elect some Nazis".