Having said all that, recently I discovered a subreddit that was all about illegal activity. As someone who respects rules and laws of society, I found it appalling how many posts and subscribers there were to this subreddit. I will not mention the sub's name because I don't want to promote it, but it has several hundred thousand followers.
I know Reddit does have some rules about what kind of content is not allowed. You see what kind of content is prohibited here: https://www.redditinc.com/policies/content-policy
The closest thing they have in regards to illegal activity is number 7 that says: “Keep it legal, and avoid posting illegal content or soliciting or facilitating illegal or prohibited transactions.”
This sounds like anything illegal would be against policy, but apparently it is more about transactions rather than posting about illegal information. I tried reporting a few posts that were clearly promoting illegal activity and I got responses back from Reddit saying that the posts did not violate their policy.
Reddit also does not make it easy to report communities that are like this. You cannot directly report a community no matter how harmful it is. You have to report individual posts and hope they take some action against the community when they start seeing these reports. You can also contact Reddit here: https://www.reddit.com/report which I tried as well and so far no action has been taken.
I still like Reddit in general, but they really need to take more responsibility in putting a stop to content and communities like this. I know people will say they don't want censorship and that it might be subjective as to what is appropriate and what is not, but for communities that are blatantly disregarding laws and are actively encouraging illegal behavior, they need to be shut down.