I think that has far more to do with this site being relatively low-traffic. Double the traffic, while keeping the exact same rules and topic, and it would become unreadable. It's easy to "moderate" when people clearly break the rules; but "moderation" can't do anything if the only problem is that most comments are uninsightful. Large numbers always ruin things, in real life or online.

It's controversial, but if the average IQ was 120 rather than 100, I doubt you'd have 1/10th as many issues on massively popular social media; most of the moderation issues would go away.