Very few, but Zimmerman's position was even worse. According to Zimmerman, Martin had noticed that he had the gun. Zimmerman's jacket had fallen open while he was squirming underneath Martin so he could move his head off the concrete and onto the grass. Martin said, "You're doing to die tonight motherf*****!" and tried to grab Zimmerman's gun. George got to it first, and used it immediately.
That's Zimmerman's story. It makes sense and is consistent with the known evidence.
Once Martin noticed the gun, the fight became about who could get to the gun first. Forget the fistfight, this was a to-the-death battle for the gun.
Then why condemn Zimmerman for protecting himself?
There are obviously many factors at work, but here's one: I bet if a pollster asked black Americans who disagree with the verdict about the details of what happened that night, they would be shown to be abysmally ignorant of the known evidence and of Zimmerman's description of what happened. They hide from the truth, so Zimmerman has to hide from them.