F#@%ing Profanity.

Admission time. I swear like a sailor. A habit made worse by the extremely creative nature of my significant others cursing. In professional settings I maintain dignity and keep from offending any ones delicate sensitivities, or teaching my 4 year old niece new words to future embarrass her parents with. That said, I hold strong to the idea that there is a time and a place for cursing. The satisfaction of questioning the paternity of the jerk who just cut you off. Or when attempting to put together Ikea furniture. Profanity is a way of venting steam, with out damaging people or property. That said, with only a few exceptions, I have noticed that genre books, even romance novels, swinging back towards the way of the innuendo. I read copious amounts of urban fantasy, romantic fantasy, Sci Fi, pretty much if it is in the genre section of the bookstore, I am scoping it out. Most of these stories feature strong female protagonists, Demon slaying, lycanthrope, vampire hunting, tough chicks who mow down their enemies with no mercy. It pumps the estrogen and slakes a somewhat bloodthirsty nature. Then this strong woman, this girlie version of the terminator(with better taste in shoes of course), will open her mouth to tell off the next big nasty. Instead of the guttural sound of a perfectly wonderful profane word, what do we get? "Stay back you big meany!"
I bring this up because in the very same book where our heroine is not allowed to give a F-U to bad guys, the writer will chose to use graphic words during romantic or sex scenes. What makes it OK to write every throbbing, writhing, pulsing, sticky detail using harsher and dirtier words, but not allow the character herself to use them? Is it and old fashioned ideal that a lady does not cuss? Or perhaps that a swearing leading lady would be less the righteous destroyer of evil? Or is it the fear that the reader will be offended with the language?