I understand the point. Not sure I personally agree that it is appropriate for kids, though. That you present it in a way that seems "soft" to us does not mean it is usefully preparing kids to deal with the issues - because emotionally, they just aren't ready to deal with sexual relationships at that age.
... you know the thing that really irks me about this viewpoint? Kids used to (and some still do) grow up on farms. With animals.
Breeding animals. They weren't sheltered from sex, vulgar animal nudity, and so-on. Kids used to have a pretty good idea of the mechanics of sex, having watched it happen in animals, well before they got any education.
Kids only get weird about sex because the adults around them get weird about it. Just like many things, children are easily manipulated. And when the adults treat something as normal and not a big deal, the kids do the same. When the adults treat it as shameful, dirty, to be hidden, and something to scream about? The kids do the same. Nothing to do with how damaging knowledge of sex is to kids, all about idiot adults projecting their screwed up minds onto them.
Edit: Talking this over with my husband, he reminded it goes further then I stated. Children used to (and again, in some places still do) get elbow deep in the guts of an animal to help with birthing. Because their small hands made it easier to untangle the babes when they were choking on their own umbilical cords, and other such things. Prior to child labor laws you had children going out and earning their share of the household income. Not 16 year olds, eight year olds. Because their small delicate hands were quicker on the loom. Children are quite easily hard core. Whether it's preferable to preserve their "innocence" or something like that is one debate. Whether they can handle knowing harsh realities of life, including sex, death, war, working, and so-on? That's settled by a few millennium of human history. Fooling yourself otherwise isn't for their benefit, it's for yours.