hi tkc,
don't forget that z was found not guilty due to his right to self-defence.
in my view, the issue is the same as always. you permit guns in any environment, you are going to have the set of problems that goes with their deadly firepower.
for whatever reason, martin was beating zimmerman. there are many ways a person can defend themselves. not all include deadly force. but where everyone is permitted a gun, everyone else is more likely to want one too. so that they are not at a disadvantage. which means a person who is losing a fight and fears he will come to harm will likely shoot his opponent.
it's a totally crappy legal environment. but let's not forget. even when more than 20 elementary school children were shot, the us congress chose to do nothing. z isn't at fault. the whole weaponised edifice is absolutely rotten and irredeemable.