The point is that dialogs could be else than just about figuring out how to successful press those replies that grants your character most experience, it could also be entertaining!!
For example there's this movie "http://www.imdb.org/title/tt0098328/?ref_=ttfc_fc_tt" and when Joseph and Hafner as newcomers report to the commanding officer on a small base in Vietnam surrounded by the Vietcong, the commanding officer is naked and high on grass and completely ignorant about the war close while showing off a picture of a naked woman with some dialog about those bubs.
Dialogs in Fallout seems extremely polite not to offend any one. But the fact is that your character is often blowing heads off, because he/she has to. In reality that is quite disgusting smell and whatever, and if you had to continue doing it, you would probably adjust your mind to it with comments like "well, that head didn't quite fit either ...", since crying isn't making any one stop it all.
So should Bethesda allow stronger obscenity in dialogs to make them funnier, more teasing, offending etc. instead of the "try the line red color if you got enough charisma!"??