I think it's just that Reddit threads the needle on openness and moderation. Subreddits are moderated by the subreddit community. Well moderated subs attract

I think it's just that Reddit threads the needle on openness and moderation. Subreddits are moderated by the subreddit community. Well moderated subs attract and produce good content. Multiple subs on the same topic can exist, often a poorly moderated sub will be replaced by a better one.