I didn't know that, frankly I remember reading, many years ago, people saying that downvotes are not meant to express disagreement. Maybe that changed, I personally don't agree with this and only consider downvoting if someone is not being civil, is not interested in discussion, or really voicing something obviously false. I was careful with my comment, I'm not selling anything, I was just interested in maybe nudging some people towards this information.

[edit] seems I'm not the only one: https://news.ycombinator.com/item?id=19406299

It's often said, but as pointed out not the case, and ~never has been for as long as there was anything resembling policy - pg commented on it in early days.

Fwiw, I'm not really a fan of it (and don't do it) either. But it's a lot harder to upvote not-objectionable things (so many!) and not upvote things purely because you agree (tempting!) - so I suppose it makes sense. I've thought before about making a 'proof of concept' type commenting system where its designed around not/objectionable; the default as you scroll past things would be to up-vote them (automatically), only down-voting on intervention when 'this does not contribute to the discussion'. Meh, might be interesting, but I'm not interested enough that I've gotten around to it :).