Consider how many times conservative speakers have been shut down by violence: Look up Ben Shapiro, Milo Yiannopoulos, Ann Coulter, Charles Murray. Hell, even Donald Trump has had campaign rallies shut down through the use of violence. Now ask yourself how many leftist speakers or rallies have been disrupted by counter-protesters on the right.
So no evidence then, just vague arm waving and reference to anecdotes ?
Donald Trump advocates violence against his opponents, so not a good example of "leftist" political violence.