I object to that message's delivery, which seems to me to imply that an acceptable reaction to those who make that mistake are, "That was so stupid, I'm not even going to explain why you're wrong. Just do what I say." That they're worth little enough to the community as to make them acceptable targets of public ridicule. If I had made the mistake, I would feel alienated by this.

That is one reason to be short. I also use brevity when I trust someone to understand a short message, because in that case a long message implies that they couldn't understand the short message.

I hoped that the title would serve as the explanation, as it's a reductio ad absurdum.