Respected science writer Simon Singh explained this in a Guardian article as follows:
You might think that modern chiropractors restrict themselves to treating back problems, but in fact they still possess some quite wacky ideas. The fundamentalists argue that they can cure anything. And even the more moderate chiropractors have ideas above their station. The British Chiropractic Association claims that their members can help treat children with colic, sleeping and feeding problems, frequent ear infections, asthma and prolonged crying, even though there is not a jot of evidence. This organisation is the respectable face of the chiropractic profession and yet it happily promotes bogus treatments.Naturally, the BCA responded to this, but like other charlatans before them (homeopaths v The Quackometer, herbalists v David Colquhoun, vitamin quacks v Ben Goldacre), they ran to their lawyers to try to silence the critic rather than address the criticisms. They sued Simon Singh for libel. What a stupid move! Singh was obviously, absolutely correct in what he wrote. Surely he would win easily? But no, this is England. We have the stupidest libel laws in the world. And, in Justice David Eady, we have one of the stupidest judges...
I can confidently label these treatments as bogus because I have co-authored a book about alternative medicine with the world’s first professor of complementary medicine, Edzard Ernst. He learned chiropractic techniques himself and used them as a doctor. This is when he began to see the need for some critical evaluation. Among other projects, he examined the evidence from 70 trials exploring the benefits of chiropractic therapy in conditions unrelated to the back. He found no evidence to suggest that chiropractors could treat any such conditions.
Eady's ruling this week hinged on the exact meaning of the word "bogus". He decided that Singh's use of the word meant that he was saying the BCA were knowingly and dishonestly promoting useless treatments. This goes far beyond most common usages of the word (as explained by the mighty Language Log) to mean useless, false, incorrect, unbelievable or silly. It ignores the fact that Singh's second paragraph explained exactly what he meant by "bogus". It means Singh now has a difficult decision to make, for this extreme meaning will be very difficult to prove in court. He could decide to appeal against the judge's ruling. He could even end up in the European Court of Human Rights, defending his freedom to express his opinion, but this would be hugely expensive and risky. He may have to settle. Whatever he does, all sensible people should support him in any way we can.
If there are really any chiropractors out there who genuinely believe you can cure ear infections, asthma etc, you are idiots. If you badger people into unnecessary, expensive and never-ending preventative treatments, you are unscrupulous idiots. If you play on your patients' fears to try to get them to bring you their children, you are total bastards.
Chiropractic is bogus. Bogus. BOGUS!