On the earth being round - and other unnecessary restatments of known truths

This has to do with the BBC's invitation to allow representatives of the BNP to appear on Question Time.

Both Chris Dillow and Paul Sagar base their objection to this on the grounds that while rational refutation of their obnoxious views might be the best way to oppose the BNP, Question Time hardly qualifies as a forum where rational argument is given pride of place.

They're right, although I'd make my own objection on a completely different basis. The presence of the BNP on a discussion programme is objectionable per se - but is objectionable in direct proportion to which said programme could be considered to be rational. In this context, entering into discussion at all involves giving up something of what we claim - which is that the BNP's politics have nothing to do with rationality and everything to do with hatred and prejudice. Here discussion gives form to the lie that there is a case to answer - because there isn't.

I'd like here to question the liberal assumptions under which the contrary argument is made. For instance, Paul Sagar, following Mill, says the following:

"[T]he best way to tackle the BNP is to debate them: putting them on a platform makes them easier to shoot at. On this point, I’m convinced of the classic liberal arguments espoused by Mill in On Liberty: the best way to destroy a pernicious opinion is to publicly expose it; the most counterproductive way of tackling such an opinion is to try and stifle it."

I'm not clear why he is persuaded of this classical liberal argument. Mill was often rather light on evidence to support his arguments - a significant failing for a self-proclaimed utilitarian - and this section of On Liberty proved to be no exception. Add to this that of course Mill couldn't have anticipated a world where despite the scientific discoveries of the last one hundred and fifty years or so, people would seriously be arguing that Creationism be taught alongside evolution - as if the matter were undecided. He couldn't have anticipated it because he imagined rational argument alone would triumph.

Those who insist the world is flat are not invited onto the BBC's science programmes on the pretext that the best way to counter such irrationality is to engage them in rational debate. These are rightly seen rather as candidates for remedial education and possibly medical attention. So why are those who are not only irrational but stupid and vicious with it considered suitable candidates for an appearance on a supposedly grown-up discussion about politics?