A recent case in Phoenix proves that assertion, like most of the claims of cultural Marxists, to be completely and utterly false. As in the Martin-Zimmerman case, the shooter arrived at the scene in a car, while the deceased arrived on foot. In neither case was the deceased found to have a weapon. As in the Martin-Zimmerman case, the shooter claimed to be concerned for his safety because of the deceased's behavior at the time. And in neither case was the shooter arrested.
Notable differences between the cases:
In the Phoenix case, the deceased, a man named Daniel Adkins, was considered mentally disabled. Trayvon Martin may have been immature and he was probably below average in IQ, but he was in the general population of the public schools; Adkins could not even legally drive.
Adkins is not described as having struck any person, although he "swung his fists toward the window" of the car the shooter was driving and may have struck the vehicle itself. Martin bloodied Zimmerman's nose and the back of his head before the shot was fired.
The basis of the Phoenix shooter's self-defense claim is that he thought Adkins was holding a lead pipe. Adkins was holding a (possibly taut) dog leash that the occupants of the car may have thought was a blunt weapon. (The entity at the other end of the leash, a dog named Lady, was brought home unharmed.) The basis of Zimmerman's self-defense claims is that he was supine, and being beaten bloody, when he made the decision to fire.
In the Phoenix case, the shooter had the ability but not the legal requirement to withdraw to safety, specifically, to roll up the window of his vehicle (and/or to back his vehicle up, if that was possible). In the Martin-Zimmerman case, the shooter had neither the ability (being flat on his back) nor the legal requirement to flee.
The identity of the Phoenix shooter has not been made public, and we know little about him other than that he is a 22-year-old black man. George Zimmerman's name and possibly his address have been made public, as well as other details of his life like the ethnicity of his mother and father, his history of activism, etc.
A political group has called for the extra-legal "capture" of Zimmerman and hinted at killing him. No group has called for any retaliation against the Phoenix shooter.
It is not known if NBC will cover the Phoenix slaying, or if they intend to doctor any evidence in this case.