How is it ironic to give someone the death penalty who calls himself ridiculous names.
Also I don't actually believe he called himself God. I believe he called himself the Messiah, in the traditional sense that would have referred to the leader of the Jews who would have rebuilt the temple and thrown the Romans out of Judea. It would have been ironic if he had been killed by anti-Roman Pharisees, but the Sadduccees were the ones who wanted his death.