That isn't the contended part.
I agree that humans are animals mostly relying on their instincts.
What we don't seem to agree upon is 1. whether humans are principally capable of rational thought and 2. whether we should try to tackle problems rationally.
What did Nietzsche say?
Man is a rope stretched between the beast and the Overman. A rope over the abyss.
Even if I do not agree with WFN's conclusions, the premises are right.
The problem of free will is that it cannot be denied.
It does exist. Man is not victim of his own instincts. He can change the course of history. It can change anything. He can become different than animals.