So, reddit did eventually crack down and ban those subreddits. But, those places existed for about 2-3 years before they did so and grew to large numbers of subscribers. I think there's definitely policies in place for this kind of shit, but, the enforcement is another thing all together.
Also, yeah that movie is called Nightcrawler. I've seen it twice, he had a great performance of playing a sociopath in it for sure. Definitely a dark/grimey movie.