You need to defend yourself from words online?
maybe not by prospect, but i think there is not one Person on the world that would really let anyone do as they want with themselves. while i agree that the term "defending myself" maybe doesn't really fit what happens when you flame a flamer, it has been very thoroughly shown that noone can take being the mute victim for longer periods of time.
The Thing that could maybe be served as a reminder is that you are allowed to tell people to stop and, depending on the wording, to shut up, but as you said, fighting fire with fire is not the solution and...as we can see....leads to disciplinary measures to both sides.
having said that, maybe the answer should be specified.
reply a single word to the flamers, you are at risk of getting yourself banned.
"Only if you break any of the guidelines and rules while doing so. If you can stay calm, constructive and positive you are very well allowed to talk back....just don't Insult back, just because your answer isnt as bad as the other ones doesn't by necessaty mean it is a good answer."
Would have been a much more precise and answer-offering Reply if you were to ask me.