Regardless of what may or may not have happened in TX, vigilantism and defense of life and limb are two very different things. Vigilantism is hunting down alleged criminals and punishing them, whether or not they are involved in or there is evidence of their involvement in the commission of a crime. It borders on terrorism, and is unacceptable in any civilized society under rule of law.
Defense of life or limb is different, you have the right to act in defense of others to prevent their death by persons or animals. Yes, I would take on a person trying to break into the neighbor's house if I knew for sure that they were home and their lives were potentially in danger. Otherwise the break-in is a burglary, and burglary is not punishable by death in our country.
I say watch fewer movies, be less scared of others, and be less judgemental in general. If you don't know exactly what is going on, don't intervene, and don't let your fantasies run away with you. And remember, you will be tried under the "reasonable man" rule (i.e. would a reasonable man have acted in this manner?).