[greenishness]

He didn’t have to attack Zimmerman and he could have backed off at any time without getting shot. So Zimmernam has the right to stand his ground but Martin does not?

I think he meant if Martin backed off he would not have got shot.

[FewsOrange]

Matin did back off, as we can hear in the 911 call he actually runs away, Zimmerman follows him (Zimmerman admits this in the 911 call as well). Then when Martin tries to defend himself from the stalker he gets shot.