You really don't know that Jesus was tortured by the Romans? Really? The hell you think the crown of thorns were, an apology for what the Pharisees forced them to do? An acknowledgment that Jesus's power superceded that Pontius Pilate and the Roman Empire? Really?
The Gospel of Matthew was not written by Matthew, none the gospels were written by those who they were attributed to. Like the other Gospels, it's full of contradictions, and they contradict each other. They also contradict logic, as the aforementioned notion that Pontius Pilate literally bent over backwards to kiss the butts of Pharisees.
If the Pharisees really believed Jesus was guilty of something, they would have had him stoned to death, no Pontius Pilate and crucifixion required.
Jesus - both of them - were arrested, tried, and sentenced to death for sedition. That was the charge, and that's why he was executed. Well, one of the anyways,,,