The anger itself is natural, when there are sexual predators who kill on the loose, and when the law has been unable to keep them locked up. But there are very few such sex-murderers and no evidence that paedophilia is more prevalent now than before. There are child prostitutes on the streets of London; but so there were in Edwardian times. From Cleland to Walter to Laurie Lee, literary evidence and anecdotage suggests a small but persistent group whose sexuality becomes locked in early experiences and who then interfere with children.
But what we have now is a combination of a sex-obsessive culture and, within it, the high-profile "paedophilia thing". You see this, usefully compacted, in the tabloid coverage of the awful Sidney Cooke, a man who should never have been released.
On page two of Monday's Daily Star we get: "Let 'em rot ... Perverts could be caged forever". Barely a centimetre away the paper proudly displays "Plumber's mate Amanda" and her "impressive domes". Mildly tasteless? The Sun ran its attack on "filthy beast" Cooke a page after ogling cheerfully at naked "hairdresser Jodie Shaw, 18" and a few pages before an Ulrika Jonsson interview in which she poses in bondage gear and boasts: "I've got no knickers on!"
There's all the difference in the world between a child killer and suggestive interviews or soft-core modelling. But the border between celebrated adult sexuality and the despised perversion of underage sexuality is being constantly blurred and redrawn. The tabloids are an easy target. But more generally, we fiddle with these categories, knowing that they are not quite as easy as we like to pretend.
I found it interesting, for instance, that the child-killer Cooke, in his prison letters, uses the same sickly euphemisms that can be found in the average mainstream kiss-and-tell bonking story - "fun and games ... I needed someone to cuddle up to ... loving games ..." Another example would be Lolita the film, and the use of traditionally lush and romantic cinema techniques to describe a paedophile romance. Or the painter Balthus, now elderly and revered, whose painstaking and conservative art can be found in many coffee-table books ... but whose paintings of young girls are quite clearly paedophile fantasies.
Admittedly, this has been a difficult border to police for ages. The Victorians and Edwardians displayed paintings of boys which would now be considered highly suspect. A colleague notes that in the catalogue of the new Victoria & Albert Museum exhibition of posters, there's a pre- First World War shot of an Underground station which shows a Pears soap poster of a naked seven-year-old girl - something we wouldn't tolerate today, when family beach snaps are censored.
Coming forward in time, it was possible for paedophile leaders to be openly interviewed on Newsnight 20 years ago; and that wouldn't be possible now, either.
What is beyond doubt, though, is that today's culture is both obsessed with paedophilia and also obsessed with young sexuality. The use of ever younger-looking models for fashion shots - see, most recently, the waif- like and hairless creatures posing for Calvin Klein - and the enthusiasm of mainstream newspapers for young nude models are examples. Something very odd is going on.
On the one hand, we have murderous paedophilia regarded as modern plague when there is absolutely no evidence for this. The number of children killed by strangers has barely changed since reliable records started being collated 25 years ago. And if, as everyone seems to agree, paedophiles have mostly been abused as children themselves, then the closures of bad children's homes after recent scandals, and the spread of social work intervention, ought to mean less of it in the future, not more.
In terms of numbers of active paedophiles we may now be the victims of that same post-war secrecy, institutionalism and blindness to abuse that was part of a period we hark back to as a golden age of innocence.
And yet it was innocent compared to the explicit physical images and language that reigns today. There is less hidden abuse, probably, but there is also less nuance, less shadowiness, in discussions of sex. Is that necessarily an advance for civilisation? I wonder whether in a century's time, historians will look back with amusement at the "sex craze of the late twentieth century" as a weird social phenomenon, on a par with the Dutch tulip mania of the seventeenth century.
If sexual gratification is a new and apparently uncomplicated human right, celebrated everywhere, can we wonder that paedophiles start using the language of free speech, rights and liberation - as the Paedophile Information Exchange did in the ferment of the 1970s sexual revolution?
In a world where most sexual taboos have fallen, in which the actress Emma Thompson's alleged lesbian fling barely merits a raised eyebrow, and in which sado-masochism is treated by publishers as a cheerily wholesome hobby, on a par with gardening and basket-weaving, paedophilia is almost the last wholly unacceptable perversion.
Dea Birkett, whose film on paedophilia, The Devil Amongst Us, caused a furore recently, says that because of more general permissiveness, and the disappearance of old taboos, "we have to clamp down on that last thing, and say `hold on'. As a result, you get paedophilia inevitably blown out of proportion."
She is right: we have now come close to the situation where paedophilia cannot be rationally discussed as the relatively modest social problem it is, requiring medical intervention and secure accommodation - but starts to seem like a lurid mass nightmare in a land stalked by satanists and murderers and in which the intensity of public rage actually makes things worse.
Keeping paedophiles out of harm's way, and treating them, is both essential and expensive - yet the cost too is now under attack. We have convinced ourselves that "they" are everywhere, in scout troops, schools, any institution involving children. If we root them out, there's nowhere for them to live. We don't want to pay to keep them in police cells. But if they try to leave, we'll have their guts for garters. If you were a paedophile, driven by strong desires, would this make you more furtive and dangerous, or less? Would be likelier to seek help after this week's headlines?
Columnists are supposed to have neat answers and I don't. But I do think we have become a sex-obsessed people, who regard arousal as almost always virtuous or healthy, and restraint as unhealthy. And I wonder whether the extreme sexual selfishness of paedophilia, which turns vulnerable people into mere objects of gratification, holds a distorted mirror up to our wider sex culture. And perhaps that's where the hysteria is born.