I'm sorry, but it seems like you also have, if not an agenda, then at least some preconceptions you don't want to adjust. "I'm sure of X" really isn't much of an argument.

I remember a story of a linguist (Dan Everett, probably) working in the Amazon. He tried to convince a speaker of the language he was studying to sit with him for a few hours to help him with his grammar. He offered some fishhooks in return. The guy asked, "do you fish?", to which he replied no, and then the guy looked puzzled and said "then why don't you just give me the fishhooks?"