You'll see this behavior occasionally on any "gamified" discussion forum. But HN culture is the most extreme about this, you see it in every other thread.
* People downvote grammar-nitpicks, and "Actuallllly..."-style smarmy corrections that are more about making the speaker feel superior than genuinely helping the recipient.
* They downvote criticisms of programming languages that are currently popular here.
* They downvote libertarian political views in threads where the liberals are dominant, and then paradoxically they downvote liberal views in the next thread where the libertarians are dominating. Human nature just like a winner.
* They downvote low-quality additions such as, "This!".
* They will almost certainly downvote this comment, because it's negative in tone and speaks to HN culture, which generally doesn't go over well.
Gamification of conversation can be harmful to your mental well-being. None of these "imaginary Internet points" mean anything. Try not to troll. Otherwise, just speak your truth and take any downvotes like an adult.