Many attributes are unique to humans, but his reasoning power is chief among them. It is this that trips him up in the spiritual fantasy. He sees his mortality, fears it and creates a mythology to save himself from it.
A bunch of other critters have "reasoning power." Crows are especially astute at reasoning, figuring things out, rationalizing and planning then executing their plans. There is nothing unique about this ability in humans. But again, you are claiming the most advanced intellectual creature ever in the history of intelligent life, has this handicap where they need to create an imaginary security blanket so they can cope with fear of their mortality. Do you not realize how absolutely preposterous this sounds?
He sees his mortality because he comprehends potential immortality. Why? Because he has an intrinsic connection he can't ignore with something profound and greater than self, which he recognizes as immortal. And dude, I am sorry, you can sit here and pop off your pretentious and arrogant snorts toward "spiritual fantasy" all you like, the fact that you balk when it comes to defining yourself as an Atheist or completely rejecting the idea of God the Creator of the universe, speaks volumes.
Face it, you are a bitter man with an axe to grind. This is a personal vendetta between you and God. You feel that God somehow let you down and now you're going to make God pay. I hate to tell you this, but long after you have returned to the dust of the Earth, God will still be going strong and mankind will still be connecting with God. In the scope of eternity, you are essentially meaningless.