You misunderstood him. He's saying he's not out to disprove Hancock because Hancock hasn't proved anything, you can't disprove evidence which isn't there. E.g. prove to me that unicorns never existed.

Instead, what he's done is gone through and discussed what's wrong with the logic that Hancock is using to come to his conclusions. i.e. here's what science have found, and none of it points to unicorns. When you thought A, you were forgetting B. When you said C, you were ignoring D.

It's a rational way to approach an irrational argument.