It's only the second day since Craig Stephen Hicks and a lot of atheists are already tired of hearing about it. Although the police have been careful to avoid accusing Hicks of a hate crime, everyone else has been quick to leap to that judgment. Of course, rather than blame anti-Muslim sentiment everyone assumes that atheism itself acted as motivation for Hicks' crime.
We've been saying it for a while but it needs repeating: atheism doesn't inform our actions any more than not believing in unicorns informs yours. That doesn't mean religion can't be a factor in an atheist's behavior, it means that our non-belief isn't justification for action. Religion can still motivate us to react, to speak up or act in response to something that believers are doing. It can make us fear for our safety, and fearful people are more likely to lash out. History shows us several examples of this.
In 1793 French revolutionaries passed a law outlawing religion and religious belief. This anti-religious behavior added to the atrocities that history now calls the French Reign of Terror, as priests and devoutly religious people of all social and economic stations were tortured and murdered. In 1917 Russian revolutionaries formed the Soviet Union and seized all property and wealth of the elite including churches, beginning an era where religion was discouraged, suppressed or drafted to support the leadership depending on circumstances. In 1966 Mao Zedong duplicated the Soviet uprising through his "Cultural Revolution" with similar actions and results. In 1975 the Khmer Rouge took Phnom Penh and began a Communist dictatorship that oppressed religion and cultural minorities alike, classifying people into categories and starving or executing them as they saw fit.
Atheists will quickly point out that these actions were political, and they're correct. But the fact that religious followers were explicitly targeted can't be ignored. Atheism doesn't justify this, but humans can use any excuse to misbehave as long as we have reason to categorize people as "other." Why do I bring this up? Not to suggest that atheism is a religion or that it's just as guilty of promoting atrocities as any religion. It's to point out that even though we don't believe in any gods or follow any religion we can still rationalize our bad behavior, just as Craig Stephen Hicks did in Chapel Hill.
Human nature being what it is, we'll probably never completely excise our violent urges, and I'm not sure that we would be advised to do so. It's one thing to channel such urges into productive action, but another to remove them completely. It's not that these urges are bad in themselves, it's that allowing those urges to provoke us to bad behavior is the problem. What we need is not a lobotomy, we need to learn self-discipline. Atheism is not a cure for violence or any other bad behavior, it's just one less excuse for it. We can still find motivation through greed, fear, politics and so forth but we can't claim a divine mandate for it.
Given our tendency to rationalize our behavior I think it's in our best interests to police ourselves rigorously when someone suggests we need to kill all the Muslims or lock up all the Christians. No, it's not something that comes up often but I do see it from time to time. And when I do I'm quick to stomp on it. For one thing it's a deeply immoral thing to suggest, and for another it doesn't solve the problem. Religion spreads through indoctrination and justifies itself through fear. We can try to suppress indoctrination by force, but that simply aggravates the fear. Indoctrination goes underground and gets enhanced by fear of discovery and oppression. It didn't take long after the fall of the Soviet Union for the Russian people to return to their old religious habits, minus the aristocracy. Their reasons for clinging to religion for comfort were never taken away, in spite of the promises made by Communists. The Socialists of Western Europe offer a much better model by taking away the insecurities that drive both conflict and religious devotion.