These ancient conquerors lived in a very different world to us, and where they got was because of their own hard work," he added. "We can't really judge them morally."
That is a load of crap. Murder, rape, stealing have always been wrong. Just because you add a few thousand years to an murder it does not change the nature of the act.
That is like saying the white farmers who took slaves and beat them were not doing anything wrong. Maybe the acts by blacks during the Rodney king riots were justified. Maybe we can't judge the communist, or the Nazis, or the recent terrorist because they lived in a very different world than we do today.
The unchanging nature of morals allows us to judge them.