I for one have never implied that sex is shameful or "hidden away and treated like it's dirty." But yes, I strongly believe that sex is intimate and highly personal and should not be for public consumption by people who don't choose to witness or be present when someone else is having sex. (Hey, if you're a suburban swinger, that's your deal.)
To respond to a couple of the questions you raise - yes, I think that anyone who is living in "one room apartments, rvs, tents, school busses, yurts, basements at their parents house" should find somewhere away from their children to have sex. If that means that "you have to let your child go and stay with someone else for a few hours just so you can DTD in your own space" then again, yes. I've lived in studio apartments, shared houses with friends and shared tents with other people. And FWIW, I can't think of a single person is my group of friends who would be OK with the idea of a "tentmate" having sex with someone a couple of feet away from them.
There seems to be a lot of talk amongst the mamas who dont think people should be DTD in the same room or bed with their kiddos about culture or what is okay in "our" culture. What about people who live in one room apartments, rvs, tents, school busses, yurts, basements at their parents house, ect.? There are lots and lots of "American" families that live that kind of lifestyle. SO, they should never have sex in their own space? If you live in an RV you should only have sex when you go out into the woods and find a hidden place? If you live in a one room apartment you have to let your child go and stay with someone else for a few hours just so you can DTD in your own space? Jeeze, in my circle of friends sex is something that is not to be hidden away and treated like its dirty.
As for the PP who said they would be so so offended if they went to another country and were exposed to people having sex:
Have you ever been to the park in San Fransisco?
Have you ever lived in a communal house?
Have you ever lived in a dorm room?
There are tons and tons of places right here in this country where people are exposed to sex all.the.time. Ill bet just in my youth Ive seen at least 5 couples having sex (and not because I was there to watch). For some people, its really not that abnormal to go on a camping trip and realize that people are doing it in the tent you are sharing.
Honestly, Id be a lot more worried about my kid watching a tv commercial that implies all the bad things about sex than I would about them waking up and seeing me on top of their father.