Denial?

A mother's grief at the loss of a child is boundless, unendurable, and understandable.

 After her unimaginable loss, Fulton discovered some relief when she reached out to other moms who have lost children to gun violence. Now, she plans annual peace walks in her home state of Florida, works with legislators on gun violence laws and travels around the country speaking at colleges and churches about preventing senseless shootings.

Trayvon Martin's Mom Helps Other Grieving Mothers | PEOPLE.com:

 Sybrina Fulton’s life as she knew it ended on February 26, 2012. That’s when her 17-year-old son, Trayvon Martin, who was unarmed, was fatally shot in Sanford, Florida, by a neighborhood-watch volunteer for his gated community. 

Zimmerman testified he was flat on his back; Martin,  straddling his supine body, beat him with closed fists.
So, George Zimmerman should have just laid there and taken the beating? 

Flashback:

March 8, 2012 - Investigators receive a fax from the Altamonte Family Practice containing the medical records identifying the injuries sustained by Zimmerman on the night of the shooting: Open wound of scalp, without mention of complication; nasal bones, closed fracture; assault by other specified means.
March 12, 2012 - Sanford Police Chief Bill Lee says that Zimmerman has not been charged because there are no grounds to disprove his story of the events.

We will never know the full truth of the story, but Zimmerman's wounds suggest that his version of the story has some validity; that he was helpless, under physical assault, and unable to overcome his assailant.

April 30, 2013 - George Zimmerman waives his right to a "stand your ground" pretrial immunity hearing. Zimmerman's attorneys decide they will instead try this as a self-defense case. If Zimmerman had had a pretrial immunity hearing, a judge would have ruled whether his actions were protected under the "stand your ground" law. If the judge had ruled in favor of Zimmerman, it would have meant that no criminal or civil trial could proceed.

Whether Zimmerman was justified in confronting Martin is a moot point.  Whether Zimmerman was reacting to a deadly assault was ... not entirely deniable; some people refer to his wounds as evidence that he was in fear for his life.

Counting the story as an example of "Firearms Violence" is stretching the interpretation a bit.

The violence was initiated by Martin.  He was in control of the situation, and chose to continue beating Zimmerman ... who was helpless to defend himself against the younger, stronger aggressor.

Except that he carried a weapon, and used it.

(NOTE: Zimmerman refused to take a "stand your ground" defense)

This is "Gun Violence"?   Or is it using a weapon as the last method of defense against an aggressor?

You decide.