Moderators should keep obvious spam, explicit behavior, vote manipulation, etc... out but not to decide which content gets posted. Otherwise, let the members of the community judge content I mean that's the whole point of the site after all. You basically have to read an article before posting on a subreddit because who knows what the moderators have decided is allowed on that subreddit. For example, look at /r/games. They allow "quality" gaming content only but the definition of that is extremely subjective and the list of things you aren't allowed to post is huge (
http://www.reddit.com/r/Games/wiki/rules ). Now maybe its possible to be less strict w/ non default subreddits and make the default ones adhere to a global set of rules instead of letting each default subreddit pick its own rules. They are handed millions of users so they should be less subjective imo.