Andrew Brown argues that neither religion nor atheism can be privatized in a democracy:
Secularism is a doctrine about how society is best ordered. As such it cannot avoid imposing itself on those who disagree. To take two recent flashpoints – the secularists in the hall would all demand the abolition of faith schools, and an end to discrimination against gay people within religious bodies. Now, whatever you think of the merits of these proposals, they must involve interfering with people who disagree, and abrogating their freedom to act on their disagreements. Any attempt to privatise atheism in this respect, or to regard it as a forgiveable personal quirk which should have no bearing on public policy would be regarded by many atheists as an attempt at suppression, or even persecution. They would have a point. But the same point applies with equal force when made by believers.
Religions aren’t just collections of beliefs about God, or gods. They are also beliefs about humanity, and the proper ends of being human. As such, they form part of a large groups of more or less worked out philosophies: secularism, utilitarianism, feminism, even Marxism and modern liberalism. None of these can, by their nature, be wholly private doctrines. If they are true at all, they are true of everyone, and certain consequences follow for the ordering of society.
Read his full commentary in the Guardian.