The larger point here is not incorrect: religion is not some special spur to violence that, if removed, would leave a world of blissed-out unicorn rainbows in its wake. There are many things that move people to violence--competition for land, resources, mates, etc. Hell, if you extrapolate "resources" outward to a state level you have the only real reason anyone starts a war. After all, nationalism is derived from pride, and pride is a feeling of being owed something, whether that's a tribute, taxes, or deference (and deference is often what leads to real world gains via trade negotiations, say, or military showdowns). To be satisfied, nationalism demands something it can touch.
No, the reason people like me find religiously-inspired violence so nonsensical is because, of all the tangible things humans kill other humans in order to claim--better access to food and water; a woman; a parking spot--God is the one thing that does not exist.