Atrocities were committed everywhere throughout history. When the First Crusade got to Jerusalem, they say the City ran ankle-deep in blood. Alexander the Great brutally marched his Army conquering everything in sight. The British slaughtered, divided and enslaved countless to build their Empire. The treatment of Native Americans by Settlers. Etc, Etc.
That's War. That's Empire. It's a terrible, evil thing. But Napoleon and Caesar (bastards though they are) aren't really comparable with the acts of Hitler and the Holocaust, or Stalin's purges.