I've listened to about an hour of this.
I enjoy Graham Hancocks books but he can be fairly painful to listen to. He seriously needs to get over the fact that archaeologists haven't got time for him. He sounds a bit upset lol. Usually he seems pretty cool. Carlson on the other hand, though he hasn't said much, is just calmly making his argument without trying to score points. Cool guy.
Sterner seems to be making the occams razor argument, the evidence can be more simply explained than proposing some unknown civilization that handed down it's advanced ways. I dont know a lot about it other than what i've read in Hancocks books but Shermers points seems fair imo. Hancock is speculating and he admits as much.