They both seemed like wannabe tough guys. Zimmerman = wannabe cop who beat on his ex in his spare time and flunked out of school. Martin = wannabe gang member. At least Martin was 17; teens get involved in stupid things and follow stupid fads. If anything, I have more sympathy for Martin, since I remember people who I went to HS dressing and acting like that at 17, and turning out fine 10 years later.
Zimmerman was old enough to have known better. As I said, I have no love for Zimmerman and hope that he dies forgotten and destitute. Or perhaps Zimmerman will fuck with the wrong person next time and that person will be quicker to fire than him.