Perhaps the people that read HN and then email other people are not innocent, but there's a huge gap between the number of people who comment on HN and the number of people who just read HN.

I think HN comment posters are generally innocent. I would guess that the storm came from elsewhere, or from particularly unscrupulous people who happen to read HN. Stuff like the mentioned subject ends up bringing out the paranoid people, which often causes some seriously unhinged commentary.