I posted a few comments here Does Schnorr's 2021 factoring method show that the RSA cryptosystem is not secure? my comments (and supporting comments by another user and my flags are erased without providing clarification) are being deleted. This is unacceptable unethical behavior by a particular moderator (perhaps by the involved party) or a group of moderators.
I have looked into the situation.
What happened? A user posted a comment that could be considered offensive to another person even though no harm was intended. A moderator asked nicely not to make such comments. The user then removed the comment. Then quite a few inquiries were made by you as for what happened to said comment which were all declined. Following that, you directed rather aggressive language at the moderator team about the removal of the comment(s) / the decline of the inquiry.
The mod reactions are all proper procedure and in fact even a rather nice panning out of events. It would have been well within reason for a moderator to just delete a potentially offensive comment and / or edit it to preserve intent without offending anyone.
Comments are intended to be ephemeral on StackExchange. Their primary purpose is to request clarifications and encourage improvements of posts. Sometimes we do tolerate comments not quite matching that image to stay, especially if they don't harm people and provide useful additional information that wouldn't fit the "narrative" of the post.
However, especially once there are quite a few comments under a post which add rather little to it or even have become outdated / already acted upon, moderators will clean up the comments, both so the poster can act on any remaining ones and so any interested reader has a higher "signal-to-noise ratio" with the comments. They will also do so if a comment doesn't add anything particularly useful to the post it is made on or if it violates other rules. One of those being the code of conduct which discourages speech that can easily be conceived as unkind / unfriendly.
Independently, there was a comment discussion about an answer essentially expanding on another one with an explanation that seems easier to digest. It is also acceptable to post such answers, as they add to answering the question as it may not be immediately clear how an error may cascade into falsifying a claim. The additional explanation tends to be good enough to warrant its own answer - in addition to the better tooling and more space available that would be lacking in a comment.