Not all people who have been killed in the name of religion have been killed in wars. Think Spanish Inquisition.
Whether or not the numbers add up, it's absolutely true that over the course of human history, religion has done more harm than good. It's manifested itself in the constraint of science, from Galileo to Christian Scientists not getting their kids medical treatment. It's responsible for the patriarchy of many societies, which leads to the oppression of women, which leads to overpopulation, which leads to poverty and hunger. In general, religion keeps people stupid, which is precisely what it's designed to do.