Apparently this is the case. Some appear to either forget, or ingnore, or be inconsiderate of the fact that when one legally carries a firearm there comes great responsibility. To allow a situation, in which there was no need to escalate it to the level of a confrontation in the first place, to deteriorate to the point where he felt the need to use his firearm was, at the least, ill-advised.
For all you know, Zimmerman was simply following Martin so when the cops responded on scene, he could tell them where Martin was or was last seen. If Zimmerman was suddenly attacked by Martin, how would Zimmerman have known in advance this would occur simply because he was following someone?