Martin still had a right to be where he was. Zimmerman has yet to be demonstrated to have had a right to follow a guy around a public street stalking him.
Good grief..it wasn't a public street, it was private property with gates across the road and everything. People don't have the right to just wander in, and neither Martin or his father lived there.
Zimmerman doesn't have to justify his following Martin..Martin has to justify his presence on private property of which Zimmerman is one of the owners.