For most of the first millennium of Christian history, the Church spread a veil of modest discretion over the physical suffering of Jesus. It respected the privacy of his final hours and celebrated the empty crucifix as a symbol of the Resurrection of Jesus (an event which is noted only weakly and vaguely in Mr. Gibson's conclusion). The Greek churches, even to this day, resist sensationalist presentations of the suffering of Jesus.
However, in the Middle Ages, the Western church gradually put the corpus back on the cross, though it did not present Jesus as naked, as he in fact would have been. The cult of the physical suffering of Jesus became especially strong during the renaissance. It was not always a completely healthy devotion, as the cult of the flagellants demonstrated.
Crucifixion was a cruel form of execution. After the slave revolution of Spartacus, thirty thousands slaves were crucified along the Apian Way. The death of Jesus was not unique in its cruelty, however horrible it may have been. Whether our modern methods of execution are any more humane might be an open question. It was typical of everything in the life of Jesus that he chose to be united in his death with the poor and the oppressed, a point Mr. Gibson seems to have missed.
