THIS IS DEVASTATING TO THE DEFENSE!
Oh wait, it's just Swallow popping off nonsensically again. Never mind.
I'll cut the lady some slack.
From what I read on the Internet, many other people share her view. However, I believe these people were always convinced that Zimmerman was guilty and they cannot analyze the evidence in a manner which is inconsistent with their preformed opinions. If they were more open minded and objective they might find that Zimmerman may be telling the truth when he said Martin saw his gun.
While it is true that Zimmerman's holster (worn inside the pants) was normally worn near his back pocket, it is still possible - in fact likely - that Martin saw his weapon. There is no doubt that while Martin was on top of him Zimmerman tried to get out from underneath him. Zimmerman would natural try to roll which would expose the weapon. He would not have had to roll much to expose his gun; just a tad, which he could have easily done.
It is also possible that when Zimmerman was on the ground and maneuvering to escape, the holster shifted more towards his front bringing it into Martin's view. The holster is held in place by a clip which is not so tight that it could not have moved during the attack.
I believe this "devastating" prosecutorial argument will be easily handled by the defense.
NOTE: I have read other articles wherein some people (not Swallow) have suggested that the gun would not be visible because the holster was inside the pants. I don't know where people get this stuff, but what they say is obviously untrue. Although much of the weapon is below the belt line, the grip is always above the belt line and very visible.