Why does the student say this? (replay)

Listen to part of a lecture in a history class. (P = Professor, S = Student)
(replay: Since no one knew much about the real Columbus, it was easy to invent a mythical one?)
P: Columbus was extraordinarily adaptable to the purposes of America’s nation-builders—people like John Pintard in the early part of the 19th century. And since not a lot of facts were known about Columbus, and his writings weren’t available in North America until 1816, that might actually help the process of adapting him to American purposes.
S: Since no one knew much about the real Columbus, it was easy to invent a mythical one.
P: Exactly. And this mythical Columbus became a reflection of the society which chose him…