A few years back I stopped at a blueberry farm just off the highway in Oregon. In under 10 minutes of conversation, a very nice grandmother was explaining how the Obama administration had made a deal so the UN could come in black helicopters and take all their guns, but that they were ready for it.
I got my blueberries and got out. But you can bet that there are a whole lot of people with guns and Millenarianist notions that are sure that this time it's really the end times, and that would not take kindly to government-enforced quarantines.
[1] https://en.wikipedia.org/wiki/Jade_Helm_15_conspiracy_theori...
Maybe she read about the Ruby Ridge incident, to which you only allude in the same breath as Oklahoma bombing, and knew that it was a story of a government coming to a guy minding his own business, and killing his wife, his son and his dog, for basically no reason at all.
In the US, if the military tried to quarrantine, say, Seattle, by force, what are the odds that Antifa or somebody would look at it as the Trump-run right-wing military trying to occupy Seattle against the will of the people? Would that trigger a full-out civil war? Hopefully not, but...