It's common for religious theists, especially Christians, to complain that atheists are undermining civil society by not being civil enough in their criticisms of religion, religious beliefs, and theism. It's no coincidence that some of these Christians are political conservatives who make the same complaints about liberals who are critical of conservative and Republican political policies. These demands for civility are really demands for acquiescence to indecency and injustice.
To understand why this is so, it is important to first understand the difference between civility and decency. Civility is simply politeness — being civil means not using rude, coarse language, personal attacks, and so forth. Decency is a matter of upholding minimal moral standards. Although there is much disagreement on moral issues, there is usually widespread agreement on moral minimums which constitute basic decency: don't spread lies about people in order to ruin their reputations, don't cause unnecessary suffering in others, etc.
Sadly, No! quotes an essay by Sidney Blumenthal about George Will which addresses the contrast between these two concepts:
He uses “civility” to mean manners masquerading as morals, a category of form referring less to the rule of law than to the rule of etiquette; it is more an unspoken social, rather than ethical, code. Correct behavior may make the good possible, it is not goodness itself.
By contrast, “decency,” which Will belittles, actually is about morals. And there is some history behind the word and its content. The introduction of the word “decent” into the political vocabulary can be attributed to George Orwell. In his essay on Charles Dickens, he defined the essence of the great novelist’s sensibility as “decent.” In an age of totalitarians, Dickens’s message was still contemporary.
Orwell wrote: “The central problem — how to prevent power from being abused — remains unsolved…’If men would behave decently the world would be decent’ is not such a platitude as it sounds.” Since Orwell’s use of the word, a number of liberals, intellectuals, and reformers have taken it up. “Decent” connotes a tempered moral position, one that carefully avoids righteous absolutism; it also suggests compassion and patience. The word is precisely the opposite of elite condescension, the opposite of hauteur.
Blumenthal's essay was written years ago, but it continues to be relevant today because of how conservatives call for "civility" from liberals even while demonstrating none themselves — and even worse, while defending, justifying, and promoting terribly indecent political policies. We find a very similar situation in Christian calls for atheists to be more "civil," even as they tolerate incivility towards atheists and defend, justify, and promote terribly indecent religious doctrines.
As this blog post concludes, "Blumenthal finds something abhorrent and hollow in those who strictly call for civility and at the same time give plenty of legitimacy to the most dreadful, indecent arguments and personages in the entire polity." Civility is good, but it's not enough, and it can even make problems worse when it is substituted for decency. This is often the case because those who call the loudest for civility seem to be much more interested in promoting civility rather than condemning indecency.
It's uncivil for atheists to point out that so much violence and terrorism in the world is directly or indirectly justified on religious grounds, but it's not indecent for religious believers to continue supporting the use in politics of the same religious texts and traditions which extremists have been using to justify their murders. It's uncivil for atheists to point out how unreasonable it is to claim to know that there exists a transcendent, supernatural god (as well as what it wants for humanity), but it's not indecent for religious believers to continue promoting the smear that atheists are the ones who are arrogant, smug, or intolerant.
Atheists are uncivil for arguing that society might be better off with less religion or even no religion, but religious believers can defend the indecent proposition that religion and theism are somehow critical for morality, civic ethics, and democracy. And it's atheists who are uncivil for arguing that it science is incompatible with religion and that the scientific method should lead people away from ancient mythologies, but religious believers can advocate the indecent idea that atheism, evolution, and science are responsible for the greatest evils and mass murders of the 20th century.
In most cases, the accusation that atheists are uncivil requires a radical redefinition of "civility" so that almost any sort of criticism, challenge, or public skepticism can be treated as inappropriate. In some cases, the accusation of incivility is genuine — but as I am arguing here, the accusation should also be treated as irrelevant and perhaps a part of the real problem. It's legitimate to be concerned with civility, but not at the expense of decency and certainly not in place of decency.
Why is it that conservative Christians are doing this in politics, and many liberal Christians join them when it comes to religion? I think it's because they all benefit from the perceived legitimacy of the indecency in the status quo. Challenges to the status quo, whether from liberals or from atheists, also challenge power, authority, and privileged status. Some Christians are willing to not only tolerate, but even defend indecency by insisting that those who challenge them should be "civil," which means being quiet and not speaking out sharply and passionately to attack indecency.