If you talk about the left-wing violence, you may get people making a fuss over inappropriate "moral equivalency".
Couple of points:
The use of violence is a distinct issue from the ideology on either side. To say that (perhaps) both sides were equally responsible for the violence, is not the same thing as saying that both sides have equally terrible ideology. That is just a different question altogether. You don't overlook violence because you think one side has a really bad ideology. (Of course there was probably a spectrum of beliefs on both sides.)
Second point, is that if you don't deal with the violence on the left-wing side, is that you are giving an easy excuse to the right-wing side. Right-wingers turned up with weapons?-- well why shouldn't they turn up with weapons with "antifa" around? It's entirely sensible that they should be planning for violence in that kind of scenario. So it justs hands the right-wing side a reasonable excuse to be planning for violence.
The 'right wing side' doesn't need nor care for a "reasonable excuse"; Nazism is an explicitly violent ideology, and the two cannot be separated. Initiation of physical conflict is perfectly acceptable and even encouraged in Nazism, and to a Nazi, the only immorality associated with assault and battery derives from failure to beat your opponent.
The fundamental tenet of racial supremacy is that the superior race can and should defeat its inferiors in combat, and that might therefore defines right - a Nazi has a duty to be violent against anyone who is not his ideological equal, and that is defined to include anyone who is not also a Nazi.
It's the doctrine of the bully and the thug, and until the allies showed up the fact that mere will and racial purity are insufficient for world domination, it didn't pretend to be anything else.
It's not reasonable to tolerate intolerance. Nazis want violence, because they believe that their opponents will resile from it, and that as a result, they can ride roughshod over any opposition.
Fuck that. Nazis deserve and need to be violently put down; because they believe that this is the way their opponents should be treated. Nazi ideology is fundamentally a violent attack, and violence is justified in defending society against it.
Nazism is not just right wing politics taken a tiny bit further. Even though it suits the Nazis to pretend that it is.
We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender.
This is how civilised people respond to Nazis.