I guess the moderation thing makes sense. The intent with the possibility of only addending, and forcing that to be a different color, was to avoid the invalidation of answers.
As for the offensivness thing. I guess making it available to higher level users would probably eliminate most of that. If you took a 300 XP hit for being obscene, scoundrels might think twice about it.
Then, of course you run into the whole censorship this. But I feel, if it doesn't pass the moderation standards, it should get yanked.

Just my opinion.
-Chuck