Paul Graham disagrees[0] and the current site guidelines[1] don't suggest that you shouldn't downvote for disagreement. The guidelines do suggest that you shouldn't comment on voting in the comments.

I agree with the position that downvoting for disagreement is a net negative for any site that allows it; it encourages the comments to become an echo chamber and discourages people from posting interesting opinions that dissent from the majority opinion. But HN's guidelines don't prohibit it or even suggest that its wrong.

[0] https://news.ycombinator.com/item?id=117171

[1] https://news.ycombinator.com/newsguidelines.html

That it is clumsy is not the same as that it is semantically meaningless. My disagreement is that the statement is entirely incorrect.