This whole story is very sad. The one thing we do know is that Zimmerman was armed and followed someone he thought was “suspicious” and shot him.
A concealed license is for your personal protection or the protection of those around you. It is not intended to empower you to confront folks or act like you are a police officer.
Quite the opposite, if you carry a weapon you don’t have the right to get mad about someone insulting you or arguing with you. You have a great obligation to ensure you avoid any situation that could lead to you needing your weapon.
George Zimmerman acted in an incredibly stupid manner and a young man is dead as a result. The rest we just don’t know yet (if ever).