I observed decades ago, and reported in the first years of this blog, that there is a fundamental difference between conservative violence and liberal violence. This is more apparent when one gets to look at the psychiatric cases, where the usual filters are off. The left goes on offense. The paranoid leftist fantasizes about going out and assassinating someone, or going and destroying some stronghold of what they think is oppressing the people. I have heard them say "I think about skinning George Bush alive," or being caught in a plan to blow up a federal courthouse. As things progress, they may have developed a grudge against Ted Kennedy, who they used to work for but the campaign fired them, or against Hillary Clinton, who they just don't believe is responding properly to the 100 letters they have written her appealing for help. The press uses such dodges to pretend the person who showed up with a bomb-vest at Clinton headquarters was actually some sort of conservative, but this is just a dodge. Yet even those are exceptions. Most stay true to form and want to set a housing development on fire because it harms the environment or break windows at a drive-by of Republican headquarters or a military recruitment center.
Conservatives, on the other hand, tend to be defensive, and the psychotics show this clearly. Their method is to hole up at their home, or sometimes with a bunch of associates, amassing a store of weapons and daring the ATF or the FBI or whoever to come and get them. Sometimes this is strictly local, as in developing the fantasy that the Farmington police and/or Strafford County Sheriffs have covered up not just one murder of your (drug overdosed) nephew, but a whole string of murders. They put up threatening signs, and spout off everywhere, but they don't go out and try to pick off a bunch of liberals somewhere.
Liberal projection causes them to overestimate conservative violence. They intuitively know that if they were this angry and talking about violence and collecting weapons, they would be going out and trying to hurt someone. Therefore, they think, the conservatives must be doing the same thing. This seems particularly frightening to liberals because the right is quite willing to talk about violence toward individuals. Liberal violence has a general limiting factor in that it is directed against objects rather than people. Trashing businesses, setting cars on fire, throwing rocks through windows have been until recently the more frequent liberal actions. Even the bomb vests are often not operative and the waved handguns not loaded. Just trying to get your attention, see.
I worried years ago that the limiting factors seem to be eroding. Left-wingers are increasingly shooting people [James Hodgkinson, who does not have a separate Wikipedia entry(!)], and right-wingers are increasingly going to other places to defend them or counter-protest. In the last year or two this seems to have accelerated on both sides, though I think the evidence is solid that the leftist focus on property is eroding much more quickly than the rightist focus on defensiveness.
Qualifiers: There is right-wing aggressiveness, persons going on offense, and this has always been so. Most of this is misattributed, such as apolitical Dylann Roof, Jared Loughner, James Holmes, Charles Whitman, etc, but sometimes it is real. Secondly, it isn't always easy to make a clear distinction between being defensive and going on offense. Is reconnaissance one or the other? Is going downtown to protect your city defensive or aggressive? More likely the former, but it is clearly not the same as staying in your own house or neighborhood. I don't want to get into the weeds of figuring those things out, as it is the general trend that I am noting. Going downtown to protest and throwing rocks or setting fires is clearly aggressive, though once a group is established in a place their actions might thereafter be defensive.
There is a lot of worry that there will be more violence after the election, with competing predictions whether it will be worse if Trump wins or Biden wins, with further discussion that it matters how the fairness of the election looks. I think further violence is likely, but I don't know that this is suddenly explosive. We have had intermittent urban violence for decades, including when a sports team has won or lost a championship. There is some difference in that young white people are trying to take over the protests for political purposes more related to more thoroughgoing change in the American system, as contrasted to protests of anger with a focus on local changes that have been more common from black communities over the years. Interestingly, the latter has a somewhat defensive quality of protecting our neighborhood, protecting our people, even though the protests are aggressive. I don't think you can define the radical white groups as anything but aggressive.
The limitations are eroding. The right is "going downtown" more in what they see as essentially defensive acts against protestors. But they aren't going to officials or opponents houses in a threatening manner, they aren't looking for random victims to shoot. The left is targeting human beings more, though much of the increase in danger to individuals comes from the collateral danger of setting fires or being in the way when they want to take over a spot. More usually, as with Operation Wall Street or Bernie Bros going to Trump rallies, the left has been provocateurs trying to get others to become violent so they can play the victim. They are very good at it. Some of them train for it. At those points you will see that what they are saying and doing has nothing to do with any aims of the protest - no shouting disagreements with Trump or Wall Street or city hall - just provocative insult.
On the right , the increase is there but still in defensive mode. It has always been "I'm prepared in case anyone wants to start anything," which is aggressive if you say it some ways and defensive in others. But nowadays I am hearing more of "It looks like we are going to have to..." or "I am telling my neighbors they need to be prepared as well." Still essentially defensive, but not the same as just waiting for others to make a move. People have general tactical ideas that position their impression whether they are attacking or defending.