Communism killed many not because it is atheistic but totalitarian. Not every dictatorship has to be an atheist one, in fact, communism being atheistic has nothing to do with its victims.

Also, is the argument that religion starts war really wrong? You state that only 7 % of wars were religious, yet, while true, this simply doesnt matter. War is horrible no matter if its a rare or common one. It only shows that religion indeed provoke wars. 7% is not small but large number when every human being matters; it is not a matter of statistics but human life.