I think the brutality must have been intentional. To the Romans, a "good death" was quick and painless. For example, if you were a citizen of Rome, then even if you were sentenced to death, you were guaranteed a beheading instead of something slower. To the Greeks, keeping the body intact was very important. That's why they gave Socrates hemlock to drink; even though it must have been agonizing, it was respectful because it maintained the integrity of his body. Jesus' death mixed the worst kind of death to both Greeks and Romans, and also fit in the curse that the Jews had against anyone who died hanging on a tree. This offensiveness is called out explicitly in 1 Corinthians 1 https://www.biblegateway.com/passage/?search=1+Corinthians+1...