The guy is trying to protect himself from people who will try and use his services and then when they see a place they like they turn around and use their lazy uncle, niece, sister or who ever ells they know with a license to complete the transaction effectively cutting him out of the deal. This happens all the time and its very frustrating for a buyers agent because it costs time and money to show properties.
Buyers are known to flake and thats why some agents will only take on clients with an agent exclusive agreement before they invest anything in them. I see where he is coming from but I think his approach is wrong.