The problem is that content providers have a financial incentive to create an environment that penalizes anything controversial and rewards unchallenging posts that regurgitate whatever the lowest common denominator of that community happens to be. Reddit is by far the worst example of this, but it feels like HN is becoming more like that as time goes by.

Last year I read HN many times a day and often staying awake two days in a row, I've observed that phenomenon you're describing. And from what I've observed, that crowd is different (and stonger) when the Americas are awake than when Europe is awake.

There seemed to be less downvoting around 10am GMT than at 6pm GMT.