I posted a comment on this question: What is a word for someone who tries to comfort their mistakes by trying to reason with him or herself?, and I think someone even upvoted the comment, but my comment disappeared soon after.
The comment was "The person is rationalizing" -- or something like that.
Yes, I could have developed the comment into an answer had I not had a life apart from ELU, but leaving an embryonic answer as a comment has never been a deletion-worthy offense before.
Have the standards changed, post-mod-election, or is there is glitch in the system?
The same thing reportedly happened to a very early comment on Rosa Parks is a [symbol?] for the civil rights movement?. The user (whose name I have forgotten) was upset and there was some discussion about the deletion; the entire discussion was eventually (and understandably) deleted.