The left CANNOT tolerate free speech and critique of their ideas, beginning with the ideas that anyone who does not tow the SJW/'all white people are bad'-line is a nazi.
Time after time they show up with weapons and turn a peaceful demonstration into violence all so they can scream: Look! they were all violent nazis to begin with!
People have begun showing up with baseball hats and shields to protect themselves from antifa and sure that is taken as a sign they are dealing with nazis.
beating people up for speaking freely is exactly a nazi tactic... it is worth remembering that totalitarianism (soviets, nazis, KKK) have all started out as leftist organizations.