In cases like this, I wish people would reply with an explanation of why "unsafe" is too harsh a word rather than attempting to bury the post by downvoting it. That conversation could be helpful to others. Not seeing the post doesn't help anyone.
I do agree. Neither the HN Guidelines [1] nor the FAQ [2] are clear about what expectations they have for downvotes (unless I'm missing something). I never saw the original comment when it was, I assume, greyed out, prompting the second poster to ask about the downvotes. It is second-highest ranked now, so I assume the downvotes are a minor component to its rank.