I think you misunderstood my point. People can be tempted to kill for what they think is really important. If you are religious, this might be really important, though with Christianity you do have an argument against supporting religion with violence, originally made by Lactantius:
"Religion being a matter of the will, it cannot be forced on anyone; in this matter it is better to employ words than blows [verbis melius quam verberibus res agenda est]. Of what use is cruelty? What has the rack to do with piety? Surely there is no connection between truth and violence, between justice and cruelty . . . . It is true that nothing is so important as religion, and one must defend it at any cost [summa vi] . . . It is true that it must be protected, but by dying for it, not by killing others; by long-suffering, not by violence; by faith, not by crime. If you attempt to defend religion with bloodshed and torture, what you do is not defense, but desecration and insult. For nothing is so intrinsically a matter of free will as religion. (Divine Institutes V:20)"
Surely there has been plenty of religiously motivated violence, and Christians have, sadly, not always followed Lactantius' excellent advice. But you need something more than religion to justify violence. You need to accept the claim that force can and should be used to advance one's religion. It might lead you to violence if you think somehow you can promote religion by the use of political power. As I have argued, it's a lot harder for Muslims to reject this premise than for Christians, since Islam was founded through the use of political power.
But what about atheism? Could people really convinced that our society, if it to advance, needs to embrace atheism, be tempted to use political power, and ultimately violence, to achieve that goal? If you buy in on all the "mind virus" and "delusion" rhetoric that the New Atheists are fond of using, if you are convinced that raising a child as a Christian or a Jew is to abuse that child, etc. etc. etc., wouldn't there be a temptation to "use the ring" and force people to abandon their faith? Why not? Dawkins has already supported using the fear of ridicule to peer-pressure people out of their beliefs. Ever hear of the League of the Militant Godless in the former Soviet Union? Ever hear of the Cult of Reason during the French Revolution.
What I object to is the idea that somehow abandoning religious belief is going to eliminate violence, and that atheism somehow is going to leave us all with, as John Lennon put it, "nothing to kill or die for." As I see it, THAT view is delusional, and you have to smoke a lot of pot and drop a lot of acid believe that. My answer to Lennon comes for George Strait, as follows: