Many Catholics today, particularly apologists, when discussing atheism tend to cite the atrocities committed by 20th century Communist regimes, such as the Soviet Union and China, as evidence that atheism eventually leads to an allowance of evil. Without deference to the higher moral authority of God, it is argued, atheism naturally leads to a dismissal of the dignity of human beings and a subsequent abuse of them. However, many modern atheists argue that those Communist regimes were in fact not truly atheistic because they supposedly worshiped the state. I find this idea very intriguing and quite divergent from older forms of atheism, such as that enforced by the state in Communist nations.
Modern atheism critiques religion, especially as lived in the public sphere and daily life, for one particular sin: fanaticism. They argue that whenever someone believes something is deeply important, when someone holds strong convictions, that this naturally leads to a willingness to fight and even kill to defend or enforce one's beliefs. They cite such events as the Crusades, Inquisition and modern Islamic terrorism to justify this assertion. As I said above, they also cite examples of this in violent atheistic regimes, such as Soviet Communists, saying that because Communists fought and killed for the sake of the State, they thus worshiped that state and so were religious fanatics. Those Communists, however, said that they were enforcing atheism specifically, not just the rule of their State. It was ideological as much as political. Essentially, then, modern atheists are asserting the position that atheistic Communist regimes believed in atheism with such strong conviction that they turned it into a religion; by their willingness to fight to spread and enforce atheism, their atheism became religious and so was no longer truly atheistic.
This is a very curious position. It also seems to be the root of the tendency for modern atheists, as well as more moderate agnostics, to assert essentially passive philosophies such as relativism and multiculturalism. In these systems, value is entirely determined by and thus dependent upon the individual, giving no one the authority to assert their beliefs as universally true for all and so ensuring that no one will have such strong convictions that they would be willing to fight for what they believe in. Indeed, these are considered the only fundamental, universal truths, itself a logical contradiction of their stance yet asserted by modern atheists quite ubiquitously. Tolerance, acceptance, "live and let live" are the only convictions of modern atheists and these are considered immune to the temptation of older atheists, such as Communists, and religious people to fight over their beliefs.
I believe this is not only held by modern atheists and agnostics but truly as a consistent policy by modern society in general, from the government down to individuals and even to international organizations, including religions. I think this is one of the primary reasons why religion has been relegated to people's personal lives, marginalized out of the public square and prevented from having any definable influence over society, most clearly seen in the more secular nations of Europe. Modern people are simply so terrified of a repetition of the Crusades, WWII, the Cold War or the terrorist acts of 9/11 that they consider any amount of conviction to lead ultimately to violent fanaticism and war. This has led to many Christians, including a large percentage of Catholics in the US, to largely disobey the Church's teachings, whether on faith or morals, rarely standing up for the teachings of the Church in their daily lives or when they vote, and why so few attend Mass and even fewer go to confession. It is seen as controversial, provocative, and ultimately fanatical to be religious with conviction.
I think the only way that Catholics today can repair this, particularly in the US, is to show that Christians can stand up for and live the teachings of the Church, to live out our faith in our daily lives, without being violent, judgmental, hateful or ideological in any way. The Holy Father Pope Francis has tried to assert this fact, but it seems to me that modern people's deep-seated fear of fanaticism remains strongly resistant to his urgings, even when saints like Pope John Paul II and Mother Theresa prove that we as Catholics can stand up for and live out our faith without ever resorting to violence or hate of any kind. We must show the world that the love of Christ is peaceful, but also that peace comes first and foremost through truth and the justice it engenders, not through lies and ignoring people's sins and the harm they do to the common good of society.
As Catholics, we also need to make the distinction between right and wrong on principle, not simply on results. Peace is a good but not the highest good; when grave evils are being perpetrated or dangerous falsehoods are being spread, pointing out these evils and lies with clarity and conviction will ultimately bring peace, but it will first bring division, since people do not automatically renounce the wrongs they do simply when they are corrected. The teachings of Catholicism do not permit any violence which is unjust according to the standards of the Gospel, and so whenever a Catholic does commit violence contrary to Church teaching, they cannot be said to represent the Church. However, some worldviews such as atheism which lack a permanent and fundamental affirmation of the value of human life are in principle open to the kind of violence perpetrated by atheistic Communist and Fascist regimes of history. The only way atheists can truly refute the violence of these regimes is to redefine them as religious rather than atheistic, but this is to make the additional claim that religion is intrinsically violent, as explained above, whereas atheism, lacking any strong conviction, is essentially peaceful. The question we must ask ourselves when presented with this dilemma is: what is the price of peace? What are we willing to ignore for the sake of peace? Evils will occur whether people are religious or not, but only if we believe in evil and can clearly distinguish it from the good are we able to recognize evil and fight against it in the right way.