Che was simply a psychopathic serial killer. He had a lot in common with John Wayne Gacy.
It is believed he was a Good Samaritan on a pilgrimage around the world, trying to save the forgotten, and was assassinated while on his quest. It a sort of Christ-like myth, since it conforms with the extreme self-sacrifice of the good preacher who is martyred to redeem the world.
Che could not fit in the civilized world. Castro realized there was no place for him after the revolution in peace time communist Cuba. He was sent on a suicide mission to rid Castro of his Che problem.