I see No Country for Old Men as partly a study on the conflict between those who believe in free will and those who don't. The villain, Sugar, has shed the illusion of free will, and has thrown himself into the thing he knows motivates him: prejudicial termination of other people who stand in the way of his current clients' goals.
This is in contrast to the backdrop of a community reeling with outrage at and fear of his brutality. They see him as an agent of evil, some sort of amoral if not immoral demon, a spawn of the escalating narco wars. Normal people imbue themselves and others with causative powers. This is exemplified by the exchange with Norma Jean.
"You don't need to kill me. I ain't got any money."
"I'll flip a coin. It's the best I can do. Call it."
"No, I ain't doin' that. It ain't the coin that decides. It's you, it's always been you."
"I got here the same way the coin did. Call it."
It's only first year philosophy students who will consider this a real ethical conundrum.
Or people who still believe in free will.
If a serial killer chooses their victims by using a random number generator, the algorithm isn't going to be tried for murder.