User A has provided an answer to user B's question. User B (the OP) responded to the answer:
No, you CANNOT [do that thing suggested in your answer]. If you do [your suggested aproach] -- well guess what? IT WILL NOT [DO WHAT I WANT]. INSTEAD, it will try [loading a different resource] WHICH OF COURSE DOES NOT EXIST. So, your answer is WRONG and USELESS.
User A's answer seems to be technically sound and very comprehensive. The OP, on the other hand, is quite a novice and has quite likely misunderstood the answer.
Obviously, the comment is necessary for User A to learn that User B still doesn't understand what to do, so it probably shouldn't be removed. It's not, strictly speaking, "offensive"; instead, it merely seems to be an extremely aggressive and vitriolic attempt at clarification. (This is not a first-time behavior; at least one of his other comments has prompted a comment from a moderator not to insult people trying to help him.)
I flagged the question as "rude or offensive", since I think that its current phrasing is begging for an argument to break out, but I understand that the OP has stopped short of lobbing proper insults. The flag is listed as "declined", but the comment has just now been edited by a moderator to a few neutral words asking for clarification.
Is there a better flag to use in this case? Should I have flagged it at all? Was my flag "declined" only as a procedural quirk, because the comment was edited, rather than deleted? The fact that a moderator acted on my flag suggests I did the right thing, but the "declined" response (combined with the general grey-area of "rudeness") leaves me wanting for a little more clarification.