Dependeds upon your definition of initialing violence. If I walk u and hit you in the face, that's wrong. If you are walking toward me with a knif yelling I'm going to get you. If at all possible I'll hit you first and as violently as possible if I can't get away.
Question is who initiated the violence?
It is never cut and dried or simple to allply as saying initialing violence is always wrong..

I know I'm picking examples that really stretch you statement but just trying to show that a clearer definition of initiating is needed.

If A threatens to punch B in the face and B responds by shooting A, which one has initiated violence?

There is a difference between force and violence. If I am standing in the doorway so that you can't leave the room, I have initiated force -- even though I haven't touched you. I am using the threat of violence to force you to remain.

You are perfectly free to respond to this force by knocking me down as you leave.

This has become an issue in dealing with the social justice warriors, because they have been taught to equate offensive (to them) speech to physical violence, and have been told it's OK to assault the person who engages in "violent" speech. It's interesting to see the shocked look on their faces when apprehended and told they've committed a crime.

Depends on the circumstances so I say the statement is incorrect. In the case of self defense, the use of force (violence) may be justified. Not initiating force may result in the loss of your own life or the life of a family member. It is a judgement call.

Seems there are a lot of attempts to introduce a gray line suggesting that unless and until another individual has caused harm or damage the victim has no right to respond. If outnumbered and the gang is threatening violence to wait would not be prudent to ensure survival. A recent news story about an elderly man in upstate New York had shot and killed to home invaders landed him in jail for using an unlicensed gun. No consideration given for the circumstances leading up to the killing, the only thing the state was concerned with was a weapon it had not authorized. There may be circumstances where someone reacted too soon, that is something the defending individual must determine, no one else.

Different context:
But sometimes socking someone consistently annoying is sooo gratifying. :)

responding to violations of individual rights is morally correct...anyone or group who violates individuals rights voids any claims their own individual rights...otherwise individual rights are meaningless...

as all else in life anything can and possibly will occur.
as humans our mere existence is predicated on the use of force. the social contract we choose to live under or are born in defines the APPROPRIATE levels of force and whence it may be used. posting generalities about situations is is simply wargaming and unless based on the reality we inhabit means nothing

It seems that Ayn Rand didn't foresee the amount of legally own firearms in the US and the conceal carry permits sanctioned by many states. Unfortunately, when you have the state of Washington initiating gun control laws and hamstringing the police from doing their job you have Antia creating violence. If that were to happen here in Az, the attacker would be laying in the street with a bullet hole in him or her.