Summations Only

Considering that atheists have themselves committed human rights violations under the banner of non-belief in a supernatural God or gods, can one successfully argue that "belief in god" is not the actual reason behind crimes against humanity? Or, in the alternative, can one successfully argue that it is indeed because of belief in God that people commit human atrocities?

I think the real crux of the issue is the human tendency to believe unsupported assertions coupled with a strong bias towards positions of emotional preference.
Religion is just a single (and easily visible) symptom of the greater disease. One could easily throw "statism," various cults of personality, and other non-religious fountains of irrational zeal into the same pot. There are plenty of irrational atheists, and it doesn't take religion to make them do bad things - the capacity for inhumanity is both ironically and tragically human.The subversion of reason in favor of authority is perhaps most obvious in religion, but it doesn't have a monopoly.

I think it's telling that, rather than realize the greater issue, the OP wants to bring atheism (what they feel is) downward towards being a religion."Atheism is so bad, its like a religion"Its as if they already think deep down that being a religion is a bad thing. And I doubt that at the surface they're willing to face that.

Yeah, "religion" is that, no doubt, but the Biblical revelation is not religion, it's the supernatural gift of the true God which can save us from all that stupid tribalism.

Some one on this forum a while back said that essentially the Christian message was that we are all one tribe.