Everyone's opinion isn't equal. The opinion of a homeless crackhead on the geopolitics of Eastern Europe is not worth as much as General Wesley Clark, for example.
if someone went on Rogan trying to talk about MMA but actually knew nothing then Rogan would immediately realize it and call the person out for being uninformed.
Rogan doesn't know much about things like war and history so when some guy comes on talking about these things in an authoritative way Rogan has no idea if the person is bullshitting or not.
I think Rogan knew that was really the point but was playing dumb (easy for him to do) because he didn't want to confront it.