Because it's a movie. It is structured and written down. Vigilantism or seizing unwarranted power is very different in real life and is illegal for a reason.
Example: Batman is a movie, which affects no one in the real world. It's entertainment and an exploration of morals. It lasts two hours and no one has their rights abridged.
We are a nation of laws. A movie is just that; a film, entertainment,...not real.
Who decides what is right? The law, which is duly voted on. Not one person with a personal agenda. The US is a democratic Republic, not a kingdom. Not a film.
