Still, look at the case against him. Are 911 operators police officers? From the reports I've read, the 911 operator told him to wait for police, but anyone who's called 911 knows that the officers don't show up right away. In Los Angeles, every time I've called 9-1-1 about the suspicious cars that park at the end of our street at night, no patrol car ever shows up unless maybe they come long after I've gone to bed. On top of that, looks like in Florida, you're not legally required to obey those instructions -- honestly, I'm not sure any state makes 9-11 instructions legally binding.
I'd love to hear Zimmerman's reason for why the kid was "a threat" that had to be solved with death. If the kid didn't have a gun or knife on him, then it's going to be difficult to justify shooting him, right? At what point is a threat deemed a good reason for shooting? Is an angry look enough?
This is a particularly American thing, probably, but if you are carrying a gun and someone attacks you, then you are expected to shoot them. Seriously, and if you think about it, it makes sense. That weapon is the first recourse for self defense because if you do not use it, then you risk giving your attacker the opportunity of taking the gun away from you.
There is no sort of "fair play" doctrine where you can only use the gun if your assailant is also armed. The possession of a firearm comes with the understanding that you will use it in any kind of situation where you feel physically threatened irrespective if the threat has a firearm or no weapon at all.