Many secular humanists argue as if faith-based ideas should play no role in democratic discourse, religion should be privatized and the public square secularised. They make three main points. None of them stand up.
His piece is a very nice illustration of an ambiguity anti-secularists regularly play on, and which I've noted before.
I know of only two secular humanist thinkers that believe that the expression of religious points of view should not be permitted in the public sphere (say "God is great" in public, or give a religious justification for opposing abortion, and they think someone should immediately start shoving socks in your mouth). This is a tiny minority of secular humanists. It is certainly not the view of this country's main secular humanist organization: the BHA. Call this strong secularism.
On the other hand, pretty much every secular humanist believes that the state, and state-institutions, should be religiously neutral, favouring neither atheism nor theism. The state should protect equally the individual's right publicly to express religious and non-religious points of view. This is the view of the BHA. Call this weak secularism. Many religious people are weak secularists.
Now carefully read Chaplin quote above. Which form of secularism is he attacking - strong or weak? It's not terribly clear, is it? The expressions employed here: "religion privatized" and "public square secularized", could be interpreted in such as way as to fit either form of secularism (whenever you see these expressions, be wary!).
In fact Chaplin's arguments only work against strong secularism, yet he says that what he is attacking is the view of "many" secular humanists.
Chaplin's view is typical of a certain sort of a religious person. They constantly tell each other what secularists think. But they constantly get it wrong. Few secularists are strong secularists. Chaplin is attacking a straw man.
Chaplin is misrepresenting many weak secularists, caricaturing their position as that of strong secularism, which, in truth, hardly anyone holds (though Chaplin probably does not do this knowingly - like Roger Trigg and Andrew Brown, he has simply bought into, and is now perpetuating, a religious myth about what it is that most or many "secularists" believe).
POST SCRIPT: What most secularists actually want is a level playing field, where the state gives religious beliefs equal status alongside other moral, political and other beliefs, not a privileged status, as is the case now. Why should adding a religious dimension to someone's political beliefs mean that their schools get state funded, their Church gets seats in the House of Lords, their religious symbols get special protection, their discrimination against homosexuals, women, etc should be made exempt from equal opportunities etc. legislation? Because they have no good answer to these questions, anti-(weak)secularists rely on caricaturing and misrepresenting their opponents instead.
POST POST SCRIPT: Interestingly, I just discovered Chaplin understands the distinction made here very well, as he actually explains it in this piece. The kind of secularism Chaplin is opposed to, it turns out, is (i) where the State allies itself to e.g. atheism, or (ii) where the state, "while upholding private religious liberty...strives to keep the influence of religious faith out of public debate and public institutions". He says the National Secular Society takes the latter view. But I can't see where they commit themselves to this. The NSS charter and principles don't seem to commit them to it. Of course the NSS will try to limit religious influence by arguing against religious positions in public debate. But that is not to say it thinks the state should start stuffing socks in people's mouths if they give religious arguments in public debate. On the contrary: the NSS defends individual freedom of speech. So again, Chaplin seems off target (though to be fair the NSS's position is to some extent ambiguous - e.g. on one page Muriel Frazer does suggest religious individuals should be permitted to argue religiously, but religious organizations speaking for them is not on. Quite what this means in practice I am not sure).
Chaplin makes it clear he is a weak secularist, in fact. Perhaps, rather than attacking "many" secular humanists, he should say he endorses the secularism espoused by the British Humanist Association (he should read their leaflet on secularism).