Much too late to save Jacqui Smith, it emerges that there is, after all, a perfectly good reason to keep the American broadcaster Michael Savage out of the country.

Belying his unexceptional appearance as a raging disseminator of allegedly contagious hatred, the man turns out to be an unreformed homeopath. Of his almost 20 or so books on alternative health, many are still available, supplying valuable information, for example, on the whereabouts of potentially harmful plants. Elsewhere, he urges uncritical adherence to the primitive credo, "like cures like". No apology or retraction of this work has ever been offered.

Though there is no way of quantifying the threat this healer might have posed to public rationality had he been allowed to visit the country, everything points to the need for caution, pre-emptive if necessary. Anyone shopping for Savage's anodyne polemic on Amazon will soon recognise this harmless stuff as a pretext for whisking fans to an array of more sinister manuals, such as Secrets of Fijian Medicine. Readers who enjoyed Savage's enchanting The Enemy Within: Saving America From the Liberal Assault on Our Churches, Schools and Military will be efficiently steered towards the same author's Complete Book of Homoeopathy, written under his real name, "Dr Michael Weiner".

There is no evidence, yet, that the author of Liberalism Is a Mental Disorder has actually devised a drug that could eliminate the condition for ever (that honour surely goes to Jacqui Smith), but, for those with eyes to see, the connections between his two strands of work are inescapable. In both lives, for example, Dr Weiner and Mr Savage attempt to voice the anxiety many people feel about life in the modern world. On air, Savage might attribute this upsetting feeling, lightheartedly, to the presence of diseased immigrants, or to the proximity of gay people, or to Al Gore's contributions on global warming.

In his Complete Book of Homoeopathy, however, that playfulness translates into a sober call to arms. "The depletion of our energy resources and the unbalancing of our ecology," he writes, "are creating a widespread state of alarm". As any observer of the holistic community can tell you, there is never any yin without yang.

Hurrying to justify his presence on its excluded list, the Home Office naturally focused, since it was easier to measure, on the offence generated by Savage the professional offence-manufacturer, rather than on ostensibly respectable work by Weiner. Even though, unlike Weiner's manuals, we can be confident his radio broadcasts did not provide incalculable support for Radovan Karadzic, when the blood-soaked Serb changed career, becoming a complementary healer in Belgrade.

But the Home Office was desperate. Once the name of Savage/Weiner had featured as the token racism-deflector on Smith's list of sociopaths, the government needed a crime that vaguely fitted his punishment.

In the recent case of Geert Wilders, invention of a relevant fiction had been relatively easy. There was a video, Fitna, in which he criticised the Qur'an. So long as people didn't watch it – and how tempting, really, did it sound? – Wilders was toast. "We have a profound commitment to freedom of speech," David Miliband said, "but there is no freedom to cry fire in a crowded theatre." Careful not to see Fitna himself, Miliband could never be accused of traducing the reputation of a fellow European politician.

Last week, with no evidence worth misrepresenting, it fell to David Winnick MP to endorse Smith's exclusion of a man nobody had heard of. Though he was keen on freedom of speech, Winnick told Newsnight, always had been, there could be no welcome here for a person who described autistic children – he consulted his Home Office crib sheet – as "brats". Yes, brats. "I can't for the life of me see why," Winnick said, "we should say to this chap, 'Come over.'" No, not even if it were on an exchange visit with Chris Moyles.

Within four months then, exemptions to Britain's cherished tolerance have advanced from objecting to the Qur'an to embrace reports of coarsely phrased scepticism about a potentially disabling illness. What next: no holidays here for chicken pox deniers? Gagging orders for anyone who wonders if this dyslexia business is getting a bit out of hand? Imprisonment without trial for anyone who thinks that the current home secretary is a shaming, incompetent clown whose greed will remain famous even after every one of her fellow colleagues has been similarly ­disgraced?

Savage's observations about autism had, as the Home Office claimed, provoked indignation in the US, followed by boycotts. Mercifully, however, there are no reports of offended people having being moved to acts of cohesion-threatening violence. Savage has no anti-autism following, no campaign, no significant allies. So, given that autistic people here are still less likely to be moved to bloodshed by this non-existent controversy, the addition of illness-denial to the official list of intolerable visitor behaviour might be a slightly careless precedent. It was not, presumably, Ms Smith's intention to add Thabo Mbeki, former president of South Africa and a once-honoured visitor to this country, to her ever-expanding rogues' gallery. Even though, in Mbeki's case, the Home Office could justifiably argue that the result of his denial of Aids was tantamount to homicidal violence. At least 300,000 South Africans are estimated to have died because of his pig-headedness.

But while Smith is allowed to make up the rules, it's futile to look for consistency. Wilders was bad enough, but the ban on Savage is so far from being a comprehensible act, so staggeringly capricious and stupid, as to defy evaluation. For all the sense it made to blither, after a day's desperate rummaging, about hurt feelings in the US autism community, Smith might as well have defended a ban on a foreign rabbit or an offensive mango. "Coming to the UK is a privilege," she raved last week, "and I refuse to extend that privilege to individuals who abuse our standards and values to undermine our way of life."

And which way of life might that be, Smith? The one whereby denying clinical evidence can get you classified as an undesirable alien? Or the way of life that offers similar deniers a homeopathic qualification and a berth within the NHS?

For guidance, in these rudderless times, one falls upon a brand new guide to our collective identity: Being British, The Search for the Values That Bind the Nation. In his introduction, the prime minister takes as his theme our nation's precious tolerance. "And it is tolerance," he whiffles, "that has helped the positive enrichment of our nation by the long succession of newcomers it has both attracted to these islands, and then helped to integrate ..."

Sure, it looks a bit out of date now. But let's be fair to Brown; at the time it was written, a few months back, he'd never heard of Savage and, in all probability, Savage had never heard of him.