I'd distinguish both, particularly the civil war (which really ought to be called the second revolution--the south wasn't trying to take control of the existing government, it was trying to separate from it), from the topic of mass confiscation. In a revolution, you have loyalists and rebels, the latter of whom have declared themselves to no longer be of the existing (parent) nation. That's psychologically different from firing on people whom you acknowledge to still be your countrymen.I hope too, How ever, Americans fought Americans in both the revolution and the civil war.
As to the proposal, I don't think most would have any problem with it, as it would be (nominally) carried out pursuant to due process of law against individuals specifically determined to be a threat.