If you have voting and subreddits you’d just end up with a community that only upvotes what they think is the best child porn (ie: Reddit’s jailbait subreddits)
Right, but that content doesn't seem to escape that specific subreddit (Or if it does, it is quickly voted down to oblivion). So in the context of moderators having to view objectionable content all day it is either content they don't mind viewing, or neatly packaged so it can be banned entirely if it is illegal.