[UncleEntity]

Probably because someone who believes that downvoting is a way to show they disagree with a comment disagreed with their comment...

(and, yes, I know this comment will get downvoted)

[detaro]

Note that "downvotes are not for disagreement" is a rule on e.g. reddit, but not on HN. (There's decade-old posts from pg about this, even back then others thought it's bad to allow this, but it's how it is.)

EDIT: one of those comments: https://news.ycombinator.com/item?id=117171