I feel you are exactly missing the point of what Eternal September means.

Yes, there is some knowledge for some internet savvy types who grew up with the internet, but a lot of people are casual users. Many people still feel anonymity gives them carte blanche to be a jerk, or worse.

The amount of effort to be online is zero, but the amount of effort of people to behave is sometimes also zero (or low), of course depending on context. HN is a lot more civilized, but if it stopped being moderated it would in time be a nasty place as well.