Attacking is generally not cool. I would rather knock somebody out that type out insults, but that's another story.
Unless specified in the forum rules, it should never happen. It's like one of those unwritten rules. While it can be good to release anger, you hurt your reputation when doing so... in your own mind and in others. I guess it depends on the person.
Anyway, it's just not cool. Don't smoke, stay in school, use protection and don't attack people in forums. 8)