The voting mechanism is a tool. People choose to use tools in whichever way they see fit. A culture will develop and form according to the norms which are set around group usage.

On HN people I've found that many people use voting to signal whether they agree (or disagree) with something. If that wasn't the case, I'd see my karma rise - rather than rise, fall and fluctuate.

As far as I can tell, if something shouldn't be on HN, we have the ability to flag a post.

I can agree that a post shouldn't needless be hammered into negative space, just as a person's point of view shouldn't be needlessly trampled on in meat-space. But I think that down-voting in general has found a place.

We can say that it might be better to never down-vote - but many users have the ability, and it's a regular practice. Neglecting the fact is a little like ignoring the fact the emperor is wearing no clothes.