Voltaire would not be approving of the Atomic bomb. This is so, because Voltaire did not support acts of hostility, as hostility
Tolerance has never brought civil war; intolerance has covered the earth with carnage.
What Voltaire is saying is that hatred and intolerance have brought war and numerous deaths, unlike tolerance. Acceptance has never caused any acts of violence. The dropping of the Atomic bomb certainly wasn't an act of acceptance or peace. It was the exact opposite. The dropping of the Atomic bomb was an act of hostility and hostility was pretty much the opposite of what Voltaire stood for