Stand your ground does not apply to this case as surveillance video and eyewitness reports seem to indicate the shopowner's life was never in any danger. The court will likely rule as such. Self-defense was the purpose of that law, the purpose was not so shopowners can play judge, jury, and executioner for petty crimes. So...I fail to see, first of all, how this case is a valid argument against stand your ground laws nor how it is a a valid argument in favor of more gun restrictions. This man will likely be going to prison, that is the current law functioning the way it's supposed to. And in favor of the victim in question.
Had the thief been wielding and brandishing a weapon, that'd be different and frankly the shopowner should have the legal right to self-defense in that event.