They took far right terrorism seriously in the 1870s. They more or less stamped out the (original) KKK while simultaneously giving the south the requisite autonomy to enact Jim Crow. Obviously Jim Crow doesn't square with our modern view but at the time the lack of some systemic way to keep the black people down was a serious grievance that a lot of people had. The government cracked down on the extremists who were starting to get off the porch while simultaneously extending an olive branch to the people who sympathized with them (and throwing black people under the bus in the process).
The same thing happened in the civil rights era. When it looked like things might get serious the .gov caved to the MLK types to prevent the Malcom X types from gaining further sympathy from the masses.
Fast forward to the 1990s and you get the ATF trilogy. Of course the magnitude of the problem was smaller than the KKK so the reaction and adjustments were smaller. On one hand the FBI cracked down on all the extremist groups (cue jokes about how the modern KKK is just a recreation club for FBI agents) but at the same time you'll notice that when the Bundy Ranch rolled around the feds didn't just shoot everyone and botch the thing as they would had they let historical precedent be their guide. Same pattern. Crackdown on the extremists while avoiding pissing off the moderate sympathizers.
Likewise hundreds of cities are reconsidering how they allocate law enforcement and social services resources after the events of this summer while also (recently, like past month) starting to crack down on protests to prevent them from getting fiery. Same pattern.
The overarching theme is pretty clear. The government never takes people's grievances seriously until there's a "real" threat of extremists getting off the porch and causing serious problems with a large body of sympathizers to back them up.
In light of that it'll be interesting to see what if any long term changes come out of the whole capitol thing.