is it possible to have a non-violent revolution or nation founding?

stalin and mao and hitler are rightly condemned for the tremendous casualties resultant in their revolutions, but should they be condemned for the violence, or for the terrific extent of the violence?

when north america was colonized by europeans, 95% (diamond, guns, germs, and steel)of the indigenous population was killed by disease, famine, and fratricide (the latter two usually being related to the confusion caused by disease). by the time wagons moved west, there wasn't much in there way (imagine how different american history might have been if there had been 20 times more injuns for the duke to fight off). everyone knows that israel's recent re-founding didn't go well, but archaelogical evidence suggests that the initial judaic conquest of canaan was quite bloody too. the walls of jericho really did come tumbling down.

essentially every area currently inhabited by humanity has been continuously inhabited for thousands of years now. if it is not possible to move in without pushing someone out, does that mean that stalin's crime in destroying his class enemies only differs from george washington's in exhausting the british by degree, not in nature?