Without trying to navel-gaze, I've noticed my own topics spark nowhere near as much discussion as they used to. Then again, I haven't made one in quite a long while!
I assume you are agreeing with me here, but in case you aren't: I believe that's a direct consequence of users who genuinely enjoy engaging in those kind of discussions getting tired of being targeted by other users who, having nothing to add to the topics in question, still act in a hostile and offensive way towards people who happen to have a different opinion.
That's not moderation, though. That's differential exposure based on the popularity of the opinion. Community voting is unaccountable (unlike moderators, who are accountable to site rules and administrators) and drowns out potentially legitimate minority viewpoints. Reddit's upvote-downvote system is good for content aggregation but very poor for debates. At least AoCZone makes you engage with unpopular opinions, because there may well be a grain of truth in them.
Fair enough, that's not "moderation" in the strict meaning of the word.
But the point I was trying to make is that reddit's moderators are not necessarily more active than AoCZone's, however discussions still seem to develop in a healthier environment down there because the up/downvote system does a decent job of filtering comments that are glaringly uncalled for.