I know I commented on this answer earlier. Part of the answer is advice that I think is not good, so I left a comment saying as much. At least one other user had a concern with the same section of the answer, but provided a different reason. Last I checked, both comments had several upvotes. The answerer never responded (at least not so I was notified) or edited, so the concerns have not been addressed... yet the comments have vanished.
The comment read:
I disagree that you should offer unsolicited help with the class. That could very easily come off as condescending (especially as she is the only woman!). I know I would be mortified - first he calls me fat, now he implies I'm dumb, again in front of the entire class?! Even though that's not the intent, stick with an apology that fits the "crime". A traditional apology token like a card or flowers would be much better.
My goal in commenting was so that the answerer will either clarify why they think this is good advice, or improve their answer by changing which act is used to apologize. If the answerer never responded, then at least future readers might see the comment and take it into consideration when choosing their actions. I didn't think this was worth writing an answer for, because my answer would have just been "What he said, except for that one bit", which doesn't add much value over the existing set of answers. So I thought it was better to help improve the existing answer.
My experience on SE is that we're encouraged to downvote and comment when we see something we think is a bad answer. The infamous answers-as-apples comparison explicitly includes this guidance:
When you see something lacking in quality, you should downvote it, comment on it for the author to improve it, or, ideally, edit it yourself.
And our own mod Catija even says as a response to Should comments be transient?
Comments should not expire at some predetermined time. Good comments may point out faults with the answer - particularly on less subjective sites.
So... why were these comments deleted?