Yes, and it's especially frustrating when you are a newer user and trying to "learn the rules" and contribute constructively. Although I understand HN is cautious about welcoming new users in general, it probably ought to welcome more warmly new users who are trying to be constructive.

Also: A couple times I have accidentally hit the down arrow. There is no undo. How does this relate to comment quality? The only remedy is to add a "Sorry, I downvoted you accidentally" comment, which I've seen people do. Although it's good etiquette that's a relatively low-quality comment.