In "Young Goodman Brown," Satan says Evil is the nature of mankind. How is this true?

This statement
from "" is Satan's voicing of the Calvinistic tenet of the depravity of man. Puritans
believed, as did the Calvinists, in the Divine predestination for the elect; all others
were evil and damned.  Since Goodman Brown counts himself among this elect, he rejects any other
idea and concludes that this evil/depravity is  in the others, rather than in
himself.