I often see questions completely answered in comments. Sometimes these are elaborate comments or even sequences of comments; in that case I suggest to the commenter that they should post their comment as an answer. But sometimes the answer to the question is trivial, e.g., “Yes, your calculation is correct.”, and the comment is a one-liner and there isn’t anything more to say than that. It seems silly to ask someone to post their trivial comment as an answer, so in these cases I write a community wiki answer along the lines of “As has been stated in the comments, your approach and result are correct”, so that the answer can be accepted and the question doesn’t stay unanswered, clogging the system.
Every once in a while (and more often recently) I get negative comments about such answers; often copy-pasted boilerplate comments like “This does not answer the question. If you want to comment on a question, do X...”. It’s a bit annoying when you think you’re performing a service to the community and the feedback from the community is that apparently you didn’t understand how the system works and we’ll explain it to you.
My questions are:
Is the practice of asking users to post their answers given in comments as answers and otherwise posting community wiki answers oneself, as suggested in the accepted answer to Dealing with answers in comments., still the recommended approach?
If so, how should such answers be phrased so as not to invite negative comments, and how can we stop people from posting negative comments about them?