>a single set of rules being applied as the mods intend.
Perhaps you haven't had as much moderator interaction as I have, but this is not the case whatsoever. Some subs will have 30-100 mods and each will apply the rules differently per their own interests or pet peeves.
Well, then let's qualify HN as a mid-sized subreddit with a mostly well-behaved subscriber group and bunch of tricks (such as non-trendy UI) that reduce moderation load, making it possible for a single person to handle it.
Point being, comparing HN to Reddit is a category error; HN is in the same class as subreddits. This is less about HN and more about Reddit itself: Reddit is not a community, it's a network of communities on a common platform. Each subreddit is its own reality.
Perhaps you haven't had as much moderator interaction as I have, but this is not the case whatsoever. Some subs will have 30-100 mods and each will apply the rules differently per their own interests or pet peeves.