A very good point (I'm not sure if it's relevant to the book in question, as I haven't read it or if you're referring just about the conversation so far). It seems like many people will take a strong claim they are dubious about, and on finding the evidence is sparse, inconclusive, or missing, swing to assuming that statement is false, instead of a more neutral position of "I have no opinion or some reason to think is unlikely, but others think it is unlikely even if poorly supported or unsupported."
This tendency seems to be capitalized on fairly heavily in political media by finding some poorly supported assertion of the other side to criticize, which causes people to assume the opposite is true.
This tendency seems to be capitalized on fairly heavily in political media by finding some poorly supported assertion of the other side to criticize, which causes people to assume the opposite is true.