What the guy was was ignorant. There are many in the US that think they can use deadly force to protect their property. They are wrong. You may only use deadly force when your life is in immediate danger. Even if the you had walked in his front door he would not be allowed to shoot you. You may only use the same amount of force that is used against you. That means if your attacker has a loaf of bread in his hands you cannot hit him in the head with a hammer.
I look at this guy when ever I pass by his stand. He looks like he has very few customers if any. I would think that there may be loneliness issue here. He was just trying to make friends. He probably has a thing for the cops.