Perhaps it's because Spirit narrating, his dad Strider not being there at his birth pretty much explains that he's either: dead, left, was taken away, 或者 HAD to leave. So things could happen, he could return. Plus this only made Spirit 更多 determined, stronger & protective
Maybe it's because in the wild stallions fight over possession of a herd and it's often stallions fighting their own colts and the fights NOT over until one either backs off 或者 one dies.
His father is in the film. His father IS the Eagle. His father is dead but his spirit became an Eagle. Apparently he got killed 由 his brother. I am studying this sort of spiritual thing.
