When is it appropriate to flag a comment?

Question

I read the entry in the FAQ, but that only mentions obvious things such as "abusive, off-topic, or inappropriate content." What about the gray areas?

I mention this because my recent question: In the book/movie Sphere, why was the space craft built with aerodynamics? attracted a person who appears to be quite passonate about their response. In the comments on his answer there appears to be an escalating argument about the merits of his answer.

But what I actually find inapproroate is that on the main question he suggests that I have selected the wrong answer, and that I should choose his. I referred him to this meta question/answer: What happens to an obviously correct answer that is never marked (and no other answer is marked)?. But I'm wondering if his comment should be flagged as inappropriate, so that he learns not to be so aggressive.

Answer 1

The comment flag reasons give an idea. Anything that doesn't respect the etiquette rules (“civility is required at all times”) will be deleted by a moderator if it comes to our attention, so flag as “rude or offensive”. Furthermore, comments are only intended to request or provide clarification on a post or suggest improvements; discussion should happen in chat. If you feel that a comment does not meet these intents, flag as “off-topic” or “too chatty”. If you feel that a comment has served its function and will not be useful to future visitors, flag as “obsolete”. For more discussion of comment flagging, see the comment voting and flagging FAQ on the main Meta, and this essay on when comments should be deleted.

When you see a post with many flag-worthy comments, don't bother flagging them one by one; instead, flag the post for moderator attention and describe the situation in the flag reason (e.g. “flame war in progress in the comments”).

Here, I've deleted all comments except Jeff's initial objection, as the comment discussion doesn't seem to be going anywhere.

Answer 2

In this instance, flag the aggressive comments to his answer, as they're under the 'abusive' and/or 'inappropriate' sections of the "What if I see bad things happening?" part of that linked FAQ page. You could flag his comment to the question too, as it was pretty inappropriate as well, but you handled it pretty well by replying to that comment with some education. Flag things that are out of hand, but also try to guide people back on track if things haven't gotten too bad.

In addition, you can bring questions about the flag-worthiness of posts and comments to chat, as there are often moderators there who can look into things, and provide you with feedback.