The execution was wrong because he was an innocent man. The thief on the cross admitted that they (2 thieves) were getting what they deserved, but Jesus was innocent and not deserving. Interesting Jesus didnt correct him or rail against the death penalty then.No hyperbole. Just my opinion. Slavery and sacrificing children to idols were also around during Biblical times and, like government executions, they are wrong thousands of years later. Again, tell Jesus his execution was ok because it was sanctioned by the state. You have an untenable position.
On a side note, really interesting and horrific study on the pain and suffering that the Roman's used in their punishment methods to supposed wrong doers.