This is not a carefully thought out post - but just some preliminary thoughts that have been bubbling around in my head for some time.
What set me to write a bit on this - that is, to think out loud - was not the usual nonsense about religion being the major cause of war [a simple accounting of wars in history disprove this without much doubt] - but a thought that public atheists and also those less public that one knows or casually cross paths with, use violent language frequently. I'm not thinking here about actual physical violence; about prominent historical atheists such as Stalin or Pol Pot or Hitler, but about atheists who preach atheism either in public fora or in private at bars, or family dinners or in classrooms.
Atheists preach reason, but use contempt, and a refusal to listen to any opinion other than their own.
I have encountered only one exception to this general practice.
It can be found here:
Prof. Richard Dawkins and Rowan Williams, Archbishop of Canterbury debate at Oxford
About an hour and a half, it is a rare instance of an atheist and a theist debating in a civilized manner.... come to think of it, a rare instance of civilized debate at all....