I think you better read what TWO REPUBLICANS who wrote the law have to say
http://www.huffingtonpost.com/2012/03/21/george-zimmerman-trayvon-martin-_n_1371171.html
That link refers to the “stand your ground” law, which is explicitly NOT being relied upon in this trial.
You’re conflating “stand your ground” law with the doctrine of self defense in murder/manslaughter trials. They are two quite different things.