This has been self evident to Atheists and free thinkers for centuries.
Belief in an inevitable outcome is the historic foundation of monotheistic religion and other political extremisms that have been used by charlatans and social parasites to warp the minds of their followers into being able to commit billions of atrocities since the dawn of man.
When absolute belief systems indoctrinate the weak or uneducated mind, the result is zealotry.
Be they pedophile priests, morally bankrupt televangelists, the supervisors of Auschwitz, the pilots of 9-11, the Poll Potts death squads, or the Israeli West Bank settlers, extremists who fundamentally believe forces other than free will drive our destiny are dragging our world into an epoch of moral relativism that will ultimately kill us all. Their beliefs that their leaders are divine and thus morally righteous have sown the seeds of our destruction. Whether the bloody results be witch trials or suicide bombings, the results of fools being led to believe that divine forces drive our actions has gone on for far to long.
Predeterminism is an abomination against the intellect of man. Nothing and no one independently determines our destinies either collectively or individually. Our destinies as individuals, and the collective destiny of our human society will be determined by the individual choices and actions of ourselves and our fellow human beings.
We can no longer tolerate those amongst us who foolishly hide behind the dogmatic illusion of "happily ever after" while committing heinous acts against their fellow man.
Discuss