He has a point.
I'm getting a little tired of people pointing out that a lot of the terrorists grew up in Saudi Arabia, as though that had the slightest relevance compared to who trained and sent them years later. Hell, the terrorists in England grew up in England. But that wasn't where they were trained.
The rulers of both Syria and Iran are up to their eyebrows in this mess, and it's just the latest in a history of supporting terror and mayhem over many years.