To play devil's advocate for a moment, you are basically asking everyone else (i.e. those who automatically categorize sex as special among other activities) to assume their views are false and engage with your point of view on your terms.
However, I think it's a very important point; some assumptions simply shut down discussion.
I agree here. To move the discussion a little further along if we broaden the scope a little with respect to categorization, what we are ultimately talking about here are questions of taboo in a culture that has shed many and grown generally ambivalent to the very notion of taboo. Consider for example the types of things we protect our children from in order to shield and preserve their innocence. Remember the movie Paper Moon with Tatum O'Neil, how much surprise and shock it caused to put a four letter word in a little girl's mouth. Compare that tiny breach of the cultural envelope then with the potty mouth on the little hit girl in the recent movie Kick-Ass. It caused a similar is somewhat smaller shorter lived stir. The idea that there are parents who would condone such language from a child for pay still dumbfounds me...but obviously they are out there. And many of those who "celebrate" the artistic freedom of the film would stand aghast to hear such a stream of profanity issuing from the mouth of their own nine-year olds. My question is what will be the next cultural barrier to fall in the name of personal freedom and artistic expression. Anyone remember the movie L.I.E., a "heartwarming", though not graphic story of a kid in trouble befriended and helped by the local neighborhood pedophile. You love who you love, right...whose's too judge. Today's well that's just obviously wrong is tomorrow's who gives you the right to tell me how to live. How long before NAMBLA is just the next "social group" fighting for its members' "rights." Today the notion of what they stand for is still taboo. But yesterday openly gay living was taboo, and the day before that cursing children were taboo, and the week before that adultery and fornication were taboo as was divorce without substantive cause, a month ago public religious life still received at least token public respect. So will NAMBLA remain taboo tomorrow or the day after? Should they...who has the right to say? We are not a culture comfortable any longer with the notion that some things are none of our business and some things make for a better society if made taboo for all.
We tend to feed giddy and sophisticated when we get by with breaking taboos...especially the "sexy, adventurous" ones, especially if our daring garners any sort of admiration. Those rules are for the others, the social hoipoloi, not for us, the sophisticates, who have special needs and refined pallates. But when enough people want to be sophisticated too (monkey see monkey do) the taboo falls, the society changes, and I would argue generally for the worse...the decadent little pleasure of the few becomes the wallow of the many...and for those living socially downwind it's like having a pig farm in the neighborhood, the stink just permeates everything. Now I suppose like anything else one can get used to pig stench and not notice it anymore...however, going away from it into the fresh air and coming back to it makes it very noticeable again.
Now there are some people in the world, like me, who have rethought certain notions of personal freedom, artistic license, and individualism and have come to the conclusion our old social traditions have value. They answer a number of questions we have forgotten to ask. There are things that are rightly for all and for all time taboo, forbidden, off limits, not our business. For the purposes of this aspect of our discussion it doesn't matter so much which particular things are considered taboo, but rather that taboo's exist in a society which should be respected and maintained except for the most necessary and compelling of reasons. Just because I like it, and just because no one is gonna tell me what not to do if I wanna is not compelling.
The taproot of this discussion though is not a question of taboo, but a question of human freedom. There is an innate desire in humans to be free from any constraint. It is part of us. It's in our very bones. Even suicide is ultimately negative expression of the desire for freedom, "I didn't ask to be, don't want to be, so I choose not to be." But we all know we do not possess the wisdom and intelligence to permit complete unfettered freedom. That is a recipe for chaos, for the predation of the weak by the strong.
Recall the scene from Lord of the Flies where Roger is throwing rocks at the small boy, Henry...Roger's native penchant to sadism is held in check by an invisible army of parents, teachers, peace officers, doctors, and ministers whose social mores form a protective ring about the child so that Roger always throws wide of the mark. Once he loses this inhibition at the end of the book then any evil he delights in is open to him as is evident when he kills Piggy and later tortures Sam and Eric.
We know instinctively if we were all generous and loving, then there would be no need for any restraints on our freedom, but alas we are not so uniformly generous and loving, and so we do accept that in society our personal freedom is restrained for our good and the good of society as a whole. Taboos are part of the fabric of that restraint, and we pick at their threads at our peril. If we continue, the day will come when we will not even have the rags of civil behavior left to us, and we will all stand naked and vulnerable to the whims of the strong and cunning among us. Our freedom of self expression is important and precious but it is not all that must be weighted in the balance. We have a responsibility not to let our lives, our free expression become the pig farm next door stinking up our neighbors' yards. If we must raise pigs then at least be generous enough to take the enterprise far outside the city limits, don't demand the stink be celebrated because pig is delicious and barbecues are fun.
There are long standing social taboos against promiscuity, against explicit sexual depiction/description, and against coarse discourse. In the early 20th century a breed of artists arose who chaffed at the old standards and set their genius and their will against those old taboos and were celebrated sooner or later for their forward thinking and sophistication which paved the way for others to follow. This is not to say conventions were never broken before...but never before on such a wholesale scale. Want to see what we've gained "culturally" just tune in to MTV's Spring Break or peruse some of the up and coming hit videos....a long and winding road from Shanananah and I wanna Hold Your Hand to I like Big Butts and I Smell Yo ****.
We are so careful to preserve the innocence of our children, why are we so eager to throw our own away? It baffles me.