Contains Language and sex

I have had a complaint about my writing, from someone who wanted to know why I had to include 'contrived' sex and swearing into my novel Saving Rafael. I was a bit puzzled by the 'contrived', I must say. Did she think it was artificial in some way?
I don't actually automatically insert sex into my plots, only when it feels right. In this case, with two teenagers (one sixteen, one eighteen) in a highly dangerous situation in wartime, deeply in love, it seemed to me rather unlikely that they'd refrain. I thought they'd want to make love while they had the chance. The incidence of extra-marital sex during wartime is usually supposed to go up.
As for swearing; yes, there are a few incidence of 'shit' and 'damn' in the book. These occur usually at moments of great strain; and really, if you've just heard that a dear childhood friend has been killed in battle, maybe you might feel like saying 'damn it', especially if you're a Jew in Berlin in 1942 and your life has been pretty stressful over the last few years. Similarly - if you are sheltering in the cellar of a hotel that bursts into flames over your head during an air-raid, you've been fighting the blaze with a stirrup-pump and some buckets, and the water supply fails - I think it is likely that you might say something a bit stronger than 'oh, bother.'
But this isn't just about me and my books, rather about what is appropriate for the young to read. It rather links to the edition of To Kill a Mockingbird which I gather has been put out in the States with the n-word taken out of it. So - one cannot write an anti-racist book - one that has inspired generations of kids and adults - if one includes the perjorative term common at the time. Even if the point is to demonstrate that racism is wrong. Celia Rees has written on this blog about censorship of sex in kids-lit - unless it Ends Badly and they get their Just Desserts, and I've heard teachers in a staffroom deplore Jacqueline Wilson because the situations she describes are 'too realistic.' My complainant is not a one-off. These people are real and they're out there, tut-tutting as we write.
Do they believe that if we were to portray a world in which kids do not swear, shoplift, bully each other, experiment with drugs, or get drunk or make love to each other, the young will be inspired to abjure these behaviours? Or is it just that some adults are afraid to have their fantasies of stainless childhood disturbed? The books available to me in my teens were a lot more prissy - but we were all reading Fanny Hill in brown paper covers under the desk during Religious Education.
My belief, and my writing credo, if you like, is that I write, whether for adults or for teens, not only to entertain and enjoy the act of storytelling and description, but to engage with the world. My own reading of fiction does subtly change the way I see things, not to mention breaking down the barriers between my experience, sorrows, joys and annoyances, and other people's. I don't want to be taken into a sanitised world. where real feelings are suppressed in order not to be upsetting - now that is really what I call contrived!