Not to mention "Social Club" is off limits. I guess so people can't bash R* using their own game.
I always found it hilarious that I can't use profanity in a text, but NPCs can text me "you'll be on a slab soon, M*therF*cker" all day long.
Also, if I go around cussing people out using non-stop profanity and slurs such as f*ggot (not that I do or would) I can be mic banned, but the cops do exactly that to us for hours on end. How I wish I could get THOSE trolls mic banned....
Plus - language is one thing, context is another. the logic doesn't apply to GTA V, where it steps a little bit into everything, but in a standard M-rated game, saying "oh, f***" is fine whereas a 12-year old character explicitly saying that he "f***ed my mother last night" probably wouldn't get past the censor.
So it makes little sense for the game to allow that same thing happen within it's capabilities.