News that the archbishop of Canterbury, Rowan Williams, the archbishop of Westminster, Vincent Nichols and the chief rabbi, Sir Jonathan Sacks, have joined forces in a campaign to prolong the sufferings of those incurably or terminally ill – by opposing a change in the law that would decriminalise those who accompany anyone who goes to Switzerland in search of help to die – comes as no surprise. A preference for dogma over kindness, for superstition-based moralism over humaneness, is standard fare for religion, as history too loudly attests.

Nevertheless it obliges one, wearily and with distaste, to return to the question of religion in the public domain. One would of course like to see humankind wake up from the sleep of reason that enables religious beliefs and the institutions built on them to persist. One would like a remark like Sir Harry Kroto's "the only mistake Bernie Madoff made was to promise returns in this life" to startle everyone into a great shout of laughter that would strip away the pretensions of religion and lay bare its absurdity and poverty. But while the man-made curse of religion exists, the question of what archbishops and rabbis do in the way of trying to subvert the ethical maturation of humankind has to be addressed.

So I repeat: in a free society people must be allowed to believe what they like, even stupid, ignorant and absurd things, provided they do no harm to others. Religious organisations have every right to exist and have their say, just as any other self-selected, self-constituted interest group does, such as trade unions and political parties. But religious organisations have to recognise that they are such groups, and nothing more than such groups – that they are civil society organisations like trade unions, existing to protect and promote their own interests – and although they have the same rights, they do not have any greater rights.

And here is the problem: the religions think they have much greater rights than anyone or anything else – rights to be heard, to be exempt from laws, to be awarded special privileges, to be given our tax money to run their own schools, to have representatives in the House of Lords (26 bishops plus all those retired bishops and archbishops who are now life peers), to be given hours and hours of air time on publicly funded radio every week, to have charitable status, to have their hospital chaplains paid for by the public purse, and so on and endlessly on, getting a huge slice of the pie out of all proportion to the realities: which – as an indication of the overall picture – are that about 3% of the population go to Church of England services every Sunday, less than 10% of the population going weekly to any church, temple, mosque or synagogue. And the state goes along with it!

How can this be tolerable? All religious organisations should be relegated to the status of private self-selected and self-constituted NGOs like trade unions and other lobby groups, should survive on what money they can raise from their adherents, should have the same and no more than the same rights and entitlements as any other such organisation and should stop getting privileges, money and an amplification for their views (views, never forget, derived from the beliefs of illiterate goat-herds in ancient times) from government.

What would we think if the Labour party or Conservative party received taxpayers' money to run Labour party or Conservative party schools to teach 3- and 4-year-olds their party principles? Or astrologers, crystal gazers, voodoo merchants, druids, witches – all self-described and self-selected as such, and all parti-pris in their own way?

Let us note how the archbishops and rabbi stand together to block progress towards more humane laws. Technically, of course, each archbishop is doctrinally obliged to regard the other one and the rabbi as one or more of heretic, infidel or apostate; their organisations spent most of history fighting, persecuting and executing each other; indeed all religions have to regard all other religions as getting it wrong and misleading their votaries.

But when the religions are after a common goal, as with getting our tax money for their faith-based schools, or exemption from discrimination laws, or seats in parliament, they are a united front. This used to be called hypocrisy, but no doubt modern theology has come up with a convoluted polysyllable to redefine it.

Not that a new name helps much; rubbish smells as bad no matter what you call it.