CNS News provides more insight on why Stand Your Ground is irrelevant in this case, courtesy of Ken Blackwell and Ken Klukowski of Liberty University School of Law:
Under any version of the facts, Florida’s “Stand Your Ground” law did not apply in the Trayvon Martin incident. If Zimmerman pursued a confrontation with Martin, then Zimmerman was an attacker and cannot claim SYG. If Zimmerman’s account is true that he was on the ground and Martin was on top of him, then retreat was impossible, so there would be no duty to retreat anyway. A victim in such a situation can use deadly force, but only if he reasonably believes he is being attacked with deadly force.
To our knowledge, that is the law in all fifty states. It was the law before SYG statutes were ever passed, and SYG did nothing to change it.
So why is this not common knowledge after all the reporting on the Martin shooting? Tragically, some anti-gun activists are misinforming the public. They are aided by media commentators who failed the public trust by not researching and understanding the SYG issue before presuming to editorialize on it.
The police are usually not at hand when you are attacked by a criminal. The Second Amendment guarantees the right of law-abiding people to defend themselves. And laws like Castle Doctrine and Stand Your Ground have restored that right in states where it had been eroded, not to take innocent life, but instead to preserve it.