Is a thing that does not in fact exist. The Left is absolutely obsessed with right-wing violence, always ignoring that they are violent end of the political spectrum. When you see black-masked thugs at demos trashing the street furniture and beating up people any time they have a five-to-one advantage, you can be sure they are left-wing.
Ironically, they may operate under the banner of "Antifa" (short for "antifascist") but based on their behaviour it is they who are fascists. The right-wing at the demo is likely to be calm and unmasked.
Of course, when there is violence, despite the Left starting it, they will blame the Right. This holds true from the 1936 Cable Street riots in London, to the Charlottesville riot last weekend, where the Right assembled to protest at the removal of Confederate statues, notably that of the Robert Edward Lee, commander of the Confederate Army.
Of course, there are violent right-wing activists. But they are noticeable loners who act by themselves. Rarely are there even two of them together; certainly not the mob violence of the Left.
Opposed to the Right are all the print media, almost all TV, and all the big social media platforms. However, to his credit, President Trump has not condemned the Right, merely condemned all violence. The tide is turning, and as much as anything, this is shown by the desperation of the Left.