You're just as bad as the Facebook people.
Zimmerman's actions, at every step, were justified. Let me make that clear.
Hypothetically, let's say Martin just punched Zimmerman in the face and had never straddled him or hit his head against concrete. From a legal standpoint, Zimmerman would have been justified shooting and killing Martin as a response to that action alone. His head having been attacked, he could have justifiably shot Martin to prevent things from getting worse and possibly being killed. This is the consensus this thread came to when were discussing attacks to the head, right? And yet, had that been the case, we likely wouldn't be assuming Martin was planning to kill Zimmerman.
You're assuming "Martin would have continued beating his head into concrete until someone else stopped him" with zero evidence. That's not even the most likely outcome based on what we know about both people so why is that your conclusion? Martin had been in fights before, and he had never killed anyone before. What possible reason do you have to believe that this time, he was going to keep mercilessly beating Zimmerman until he was sitting on top of a dead man in the middle of a populated neighborhood full of citizens who had easy access to the scene? Come on, don't let your emotions pull you astray here.
I'm not trolling, I'm just turning the mirror on you and showing you that using the facts to support your views works both ways.