If everyone became atheists would people still find something to fight about?

If everyone became atheists would people still find something to fight about? A common atheist argument against religion is that more deaths have been made in the name of god than anything else. That statement is said by not only atheists but theists as well because people do become over zealous in their beliefs but the same thing happens in politics, land disputes and even sports so would the world have less war if we were all atheists? Just from what I see, no. because nations of the same faith commonly fight each other like the Turks and Arabs in WWI, Chinese dynasties (most of them are Buddhists and don't believe in a god), Japanese dynasties, European nations in WWI and WWII and nations in central and south america with internal disputes. But maybe some of you can convince me.