1. dont downtalk a man in front of his woman. if he is bout that life, he may get violent. preachers are used to sonning grown men in front of their families on a daily basis and have lost touch with reality. it's like what kanye said, that atheist took him to the ghetto university...
2. atheists dont have a dogma to base their actions on, so it is hard to draw direct comparisons between the actions of an atheist and a theist. the theist may commit an act of violence in accordance with his holy book or cleric's decree, so you can implicate his religion in his actions. atheists have nothing to point to, they just beat the breaks off a man because of some other reason.
3. religious people also commit violence for no religious reason, in those instances you cant blame their religion, but you can point out that their religion is failing to make a better man out of them. this may seem petty, but many religious people claim that their religion makes the world better and that they are the only source of morality. when real life proves this to be not the case, at least in a particular instance, it is worth pointing out, obviously.
get taken to that ghetto university, brehs!