The problem is not what people believe, but the strength with which they believe it.
The wisdom of this saying struck me whilst thinking of Richard's question: can religions have special rights?
For this to be possible, there has to be something different about religious belief from, say, political belief.
The obvious candidate here is that religious beliefs - more even than political beliefs - are held so strongly that they are constitutive of identity. People don't say: "I have Catholic beliefs". They say they: "I am a Catholic." What's more they privilege this identity over others. Few say: "I'm a social democrat first and a Catholic second."
This means insults to religious belief are often construed as insults to people.
But this strikes me as irrational.
Now, all of us have beliefs that are controversial and not wholly consistent with all the evidence. In this respect, the religious are the same as the non-religious.
However, most of us recognize the shakiness of such beliefs and hold them lightly, contingently. As A.J.P Taylor said, they're strong views, but they are weakly held. This is a basic principle of rationality; we hold beliefs as strongly as the evidence warrants.
Many religious people, though, don't do this.
Giving special status to religious beliefs - either in law or in just the custom of respecting religious sensibilities - amounts, therefore, to giving a special status to irrationality.
This is surely bizarre. It's all the more so because rationality, in the weak sense I mean here, is a virtue. It encourages toleration of others, self-reflection and self-awareness. There's something attractive about Rortyan irony.
There are (at least) two possible replies to this.
One is that rationality is not the only virtue. True. But it's not obvious which genuine virtues incompatible with liberal egalitarianism are promoted by giving religions special rights.
The other is that, like it or not, attacks on religious beliefs are attacks upon people's feelings.
This generates an argument that polite people should be cautious in criticizing religion. But no more than that. Civilization is only possible if we restrain our feelings; I often feel like kicking someone to death, but civility requires that I curb the impulse. To privilege the feelings of the religious - when we know them to be irrational - is the politics of infantilization, pandering to childlike impulses rather than treating people as adults capable of restraining feelings and thinking rationally and critically.
For these reasons, I agree - for once! - with Oliver Kamm: "government should protect the free exercise of religion but not the sensibilities of the faithful."