Keeping out of the 2nd paragraph ad hominem, the first paragraph is spot on.
There are individuals on the Left engaging in political violence. I do not believe that there is any serious Leftist program of organized political violence in America today. This is an important distinction.
Organized political violence from the Left basically existed at two periods; the left-anarchist bombing campaigns of the 1910's, and the SDS / Weather Underground / etc groups in the 1970's. They're notable precisely because they were basically historical "blips," confined to the political context of their respective moments.
Meanwhile, the KKK has existed in some form or another since 18-fucking-65. It and similar groups have *always* been present, just on the fringes of Right-wing politics in America, never far from the Halls of Power.
Note this is not the case outside of the American context; Latin America and Europe both have much stronger Leftist movements that do, in fact, engage in programs of organized political violence and even terror....
But America is a center-right country. The extreme Left are either brick-throwing Antifa teenagers, or Antediluvian Academics writing Neo-Marxist theory papers in dusty offices. Neither are actually *proximal* to political power in any serious way.