Joe Horn gave two men the death penalty for robbing a house. The 911 operator told him not to go outside, and he cited the Texas code that gave him permission to kill in defense of property, went outside, and killed them. He shot one of them in the back as the man was running away.
Most of us who carry firearms understand them to be a last resort for use defense of life or serious harm, and have no desire to use them. Joe Horn didn't have to go outside, he was told not to. He didn't have to kill anyone, he wanted to. This was not a last resort by any stretch of the imagination.
He was clearly within his legal rights since the grand jury did not indict him, but to have the right to do something is not at all the same as to be right in doing it. I'm no bleeding-heart liberal, but there are limits. In my world, you don't kill people for stealing, and you don't shoot someone in the back who is running for their life.
Sorry, I just can't agree with what he did.
Edit: By the way, I don't mean to judge the man. I wasn't there that night, and clearly I was not in Joe Horn's shoes. I can't say for sure that I might not have acted in the same way in that situation. I like to think that I wouldn't have gone outside in the first place, especially having been told not to by a 911 operator, but I can't say with 100% certainty that I wouldn't have since I haven't been put in that spot. All I know is that based on the facts I have available to me (which are almost certainly not all of them), and in my comfy, armchair-quarterbacking position, I disagree with what he did.