As far as I know, f, t and w form no obscenity of which I am aware, so why can I only get ***?
I always presumed irony on the part of the mods, in that possible the nerdiest word, or acronym in this case, is censored on what is predominantly a forum full of PC nerds.
That or they are just grumpy gits with no sense of humor, or possible laughing at us from on high.