We don't know how he talked to Trayvon. He could have been nice and get hit anyways. This is what we don't know.
I'm quite sure that you don't believe this, in your heart.
I know that the kid is dead, and if Zimmerman had just done what the police told him to do, the kid wouldn't be dead. At the end of the day it may be impossible to prove exactly what happened; but the conclusion that Zimmerman provoked a confrontation, in defiance of orders from police, led to the death of this kid. And if you listen to his voice on the tapes, he clearly had anger and loathing in him for the victim. He wasn't calmly 'doing his job.' He decided to become a vigilante and is using a terrible law, passed by a bunch of assholes in FL, to defend his vigilantism.