That's even worse then, as you can excuse his behaviour by drugs. But no, he was stone cold sober when he punched Zimmerman and then processed to smash his head on the concrete.
Well its fight or flight, Martin chose to fight. Zimmerman never chose to state he was simply neighbourhood watch so got his ass beat down for stalking. The whole thing was his fault for trying to be a wannabe cop. The drugs are/ were irrelevant.