It isn't sadism. The author is hampered by lack of semantic knowledge.
The horrendous physical torture described in the Bible is actually much worse than depicted in the movie. The actual literal rendering says that He was no longer recognizable as a man!
The unbelieving liberal (redundancy) will always trip over the physical horror of the Cross, but what we couldn't see was God's transaction with Christ that was even worse than the physical because God saw and judged Jesus as though he was the sinner that you and I are.
I'm glad the movie was made.
Like vampires? Coincidence? I think NOT!