Four letter word is a four letter word

I have a foul mouth. If you've read even part of any one of my blog postings, this information is not a surprise to you. I also have kids (obviously) which means there is a portion of time during which I have to edit myself more, so that I don't end up with toddlers running around asking people "what the fuck are you doing?".
Some people are horrified that I would cuss around any of my children, as if it's the worst thing I could do. My husband's ex-wife and the mother of his two oldest children is one of these people. I could make a long list of things she does wrong concerning her children, but I won't publicly front her out. Instead, let me just say that I'd have to make up some Eddie Murphy worthy cuss words just to match her bad parenting.
This is always an interesting argument to me, when other parents, aka people-who-think-they-know-everything mention that adults shouldn't say "foul words" around kids. I can't help but ask several questions:
#1 Who decided which words are considered "foul"?
#2 Aren't there other rules that apply to children yet don't apply to adults?
#3 If you answered yes to #2, why are children expected to refrain from doing other things that adults do, but can't even be present when their parents are using the predetermined "foul language"?
I mean, think about those questions and your own answers to them. Do they make sense?
My six year old daughter's school considers "butt" an inappropriate word in their setting so they use "bottom". In my house, butt is short for buttocks, which is the proper term for that thing you sit on during too many hours of the school day. Bottom is the underside of something, which for a human, is the soles of their feet. My kids are allowed to say "crap" though it's not allowed in many homes and many public places.
Then there's the issue about rules. My kids don't get to cross the street or go to the movies with an adult until they reach a certain age. I'm guessing that, even though the age at which you allow this for your children may differ from mine, you have these same rules in your home. There are tons of things kids can't do until they're older, or adults. I don't drink alcohol, but many adults do, and they don't necessarily do it out of sight of their offspring. Cursing is one of the few rules that seems to fall on the wrong end of the double standard spectrum.
See, this is the way my husband and I look at it: I don't let my kids use the words that are fairly universally frowned upon in this country until they are old enough to know how to restrict that usage to situations and settings where they won't get in trouble for it. For example, my 15 year old daughter is about to be told, for her sixteenth birthday, that she can start "swearing" now, if she wants. My seventeen and a half year old son did not get the same privilege. It's been less then a year since he was told he could use those kinds of words because he has less self control. He would have used that kind of language and gotten detention, or worse, in school and probably offended people out in public by letting his mouth run free. He eventually earned the right to use bad language without us punishing him.
Like I said, I do have to calm my mouth sometimes. While a four year old understands when you tell them they're not allowed to say certain words they heard mommy say, a two year old does not. And it is not my preference to offend my more prudish friends with my language, so just as I don't talk religion, or rather my distaste for it, with my catholic friends, nor do I say certain words around certain people. However, when I'm hanging out with close and like minded buddies, you might want to cover your ears!