The offending quote is at 4:45
Does it have any semblance of truth?
Edit: The region is the Iberian peninsula during the time of Muslim rule there.
It might help if you specified which region and context Greene is talking about. Islam has a 1500 year history and can be found all over the world. It's hard to answer your question without knowing, and some people might not be prepared to sit through his video to get what he's driving at.